Population density is a measurement of population per unit area or unit volume. It is applied to living organisms, most of the time to humans, it is a key geographical term. In simple terms population density refers to the number of people living in an area per kilometer square. Population density is population divided by total land water volume, as appropriate. Low densities may lead to further reduced fertility; this is called the Allee effect after the scientist. Examples of the causes in low population densities include: Increased problems with locating sexual mates Increased inbreeding For humans, population density is the number of people per unit of area quoted per square kilometer or square mile; this may be calculated for a county, country, another territory or the entire world. The world's population is around 7,500,000,000 and Earth's total area is 510,000,000 square kilometers. Therefore, the worldwide human population density is around 7,500,000,000 ÷ 510,000,000 = 14.7 per km2. If only the Earth's land area of 150,000,000 km2 is taken into account human population density is 50 per km2.
This includes all continental and island land area, including Antarctica. If Antarctica is excluded population density rises to over 55 people per km2. However, over half of the Earth's land mass consists of areas inhospitable to human habitation, such as deserts and high mountains, population tends to cluster around seaports and fresh-water sources. Thus, this number by itself does not give any helpful measurement of human population density. Several of the most densely populated territories in the world are city-states and dependencies; these territories have a small area and a high urbanization level, with an economically specialized city population drawing on rural resources outside the area, illustrating the difference between high population density and overpopulation The potential to maintain the agricultural aspects of deserts is limited as there is not enough precipitation to support a sustainable land. The population in these areas are low. Therefore, cities in the Middle East, such as Dubai, have been increasing in population and infrastructure growth at a fast pace.
Cities with high population densities are, by some, considered to be overpopulated, though this will depend on factors like quality of housing and infrastructure and access to resources. Most of the most densely populated cities are in Southeast Asia, though Cairo and Lagos in Africa fall into this category. City population and area are, however dependent on the definition of "urban area" used: densities are invariably higher for the central city area than when suburban settlements and the intervening rural areas are included, as in the areas of agglomeration or metropolitan area, the latter sometimes including neighboring cities. For instance, Milwaukee has a greater population density when just the inner city is measured, the surrounding suburbs excluded. In comparison, based on a world population of seven billion, the world's inhabitants, as a loose crowd taking up ten square feet per person, would occupy a space a little larger than Delaware's land area; the Gaza Strip has a population density of 5,046 pop/km.
Although arithmetic density is the most common way of measuring population density, several other methods have been developed to provide a more accurate measure of population density over a specific area. Arithmetic density: The total number of people / area of land Physiological density: The total population / area of arable land Agricultural density: The total rural population / area of arable land Residential density: The number of people living in an urban area / area of residential land Urban density: The number of people inhabiting an urban area / total area of urban land Ecological optimum: The density of population that can be supported by the natural resources Demography Human geography Idealized population Optimum population Population genetics Population health Population momentum Population pyramid Rural transport problem Small population size Distance sampling List of population concern organizations List of countries by population density List of cities by population density List of city districts by population density List of English districts by population density List of European cities proper by population density List of United States cities by population density List of islands by population density List of U.
S. states by population density List of Australian suburbs by population density Selected Current and Historic City, Ward & Neighborhood Density Duncan Smith / UCL Centre for Advanced Spatial Analysis. "World Population Density". Exploratory map shows data from the Global Human Settlement Layer produced by the European Commission JRC and the CIESIN Columbia University
A census is the procedure of systematically acquiring and recording information about the members of a given population. The term is used in connection with national population and housing censuses; the United Nations defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory and defined periodicity", recommends that population censuses be taken at least every 10 years. United Nations recommendations cover census topics to be collected, official definitions and other useful information to co-ordinate international practice; the word is of Latin origin: during the Roman Republic, the census was a list that kept track of all adult males fit for military service. The modern census is essential to international comparisons of any kind of statistics, censuses collect data on many attributes of a population, not just how many people there are. Censuses began as the only method of collecting national demographic data, are now part of a larger system of different surveys.
Although population estimates remain an important function of a census, including the geographic distribution of the population, statistics can be produced about combinations of attributes e.g. education by age and sex in different regions. Current administrative data systems allow for other approaches to enumeration with the same level of detail but raise concerns about privacy and the possibility of biasing estimates. A census can be contrasted with sampling in which information is obtained only from a subset of a population. Modern census data are used for research, business marketing, planning, as a baseline for designing sample surveys by providing a sampling frame such as an address register. Census counts are necessary to adjust samples to be representative of a population by weighting them as is common in opinion polling. Stratification requires knowledge of the relative sizes of different population strata which can be derived from census enumerations. In some countries, the census provides the official counts used to apportion the number of elected representatives to regions.
In many cases, a chosen random sample can provide more accurate information than attempts to get a population census. A census is construed as the opposite of a sample as its intent is to count everyone in a population rather than a fraction. However, population censuses rely on a sampling frame to count the population; this is the only way to be sure that everyone has been included as otherwise those not responding would not be followed up on and individuals could be missed. The fundamental premise of a census is that the population is not known and a new estimate is to be made by the analysis of primary data; the use of a sampling frame is counterintuitive as it suggests that the population size is known. However, a census is used to collect attribute data on the individuals in the nation; this process of sampling marks the difference between historical census, a house to house process or the product of an imperial decree, the modern statistical project. The sampling frame used by census is always an address register.
Thus it is not known how many people there are in each household. Depending on the mode of enumeration, a form is sent to the householder, an enumerator calls, or administrative records for the dwelling are accessed; as a preliminary to the dispatch of forms, census workers will check any address problems on the ground. While it may seem straightforward to use the postal service file for this purpose, this can be out of date and some dwellings may contain a number of independent households. A particular problem is what are termed'communal establishments' which category includes student residences, religious orders, homes for the elderly, people in prisons etc; as these are not enumerated by a single householder, they are treated differently and visited by special teams of census workers to ensure they are classified appropriately. Individuals are counted within households and information is collected about the household structure and the housing. For this reason international documents refer to censuses of housing.
The census response is made by a household, indicating details of individuals resident there. An important aspect of census enumerations is determining which individuals can be counted from which cannot be counted. Broadly, three definitions can be used: de facto residence; this is important to consider individuals who have temporary addresses. Every person should be identified uniquely as resident in one place but where they happen to be on Census Day, their de facto residence, may not be the best place to count them. Where an individual uses services may be more useful and this is at their usual, or de jure, residence. An individual may be represented at a permanent address a family home for students or long term migrants, it is necessary to have a precise definition of residence to decide whether visitors to a country should be included in the population count. This is becoming more important as students travel abroad for education for a period of several years. Other groups causing problems of enumeration are new born babies, people away on holiday, people moving home around census day, people without a fixed address.
People having second homes because of working in another part of the country or retaining a holiday cottage are dif
Maricopa is a city in Kern County, California. Maricopa is located 6.5 miles south-southeast of Taft, at an elevation of 883 feet. The population was 1,154 at the 2010 census, up from 1,111 at the 2000 census. Maricopa lies at the junction of Route 166 and Route 33; the Carrizo Plain is located to the northwest, the enormous Midway-Sunset Oil Field, the third largest oil field in the United States, is adjacent on the north and east. According to the United States Census Bureau, the city has a total area of 1.5 square miles, all of it land. Maricopa is in the extreme southwestern corner of the San Joaquin Valley, on the first rise of land into the foothills of the Coast Ranges, with the Temblor Range, following the San Andreas Fault, trending northwest of town, the San Emigdio Mountains to the southeast; the climate of the area is hot and semi-arid, with summertime temperatures exceeding 100 °F. Freezes occur with the mean period without freezes being about 275 days. About six inches of rain falls annually in Maricopa.
The first post office opened in 1901, Maricopa incorporated in 1911. The city was named after the Maricopa Indians; the 2010 United States Census reported that Maricopa had a population of 1,154. The population density was 768.4 people per square mile. The racial makeup of Maricopa was 958 White, 1 African American, 27 Native American, 16 Asian, 2 Pacific Islander, 112 from other races, 38 from two or more races. Hispanic or Latino of any race were 232 persons; the Census reported that 1,154 people lived in households, 0 lived in non-institutionalized group quarters, 0 were institutionalized. There were 414 households, out of which 157 had children under the age of 18 living in them, 191 were opposite-sex married couples living together, 66 had a female householder with no husband present, 34 had a male householder with no wife present. There were 50 unmarried opposite-sex partnerships, 2 same-sex married couples or partnerships. 91 households were made up of individuals and 33 had someone living alone, 65 years of age or older.
The average household size was 2.79. There were 291 families; the population was spread out with 306 people under the age of 18, 112 people aged 18 to 24, 252 people aged 25 to 44, 349 people aged 45 to 64, 135 people who were 65 years of age or older. The median age was 39.4 years. For every 100 females, there were 101.7 males. For every 100 females age 18 and over, there were 103.4 males. There were 466 housing units at an average density of 310.3 per square mile, of which 268 were owner-occupied, 146 were occupied by renters. The homeowner vacancy rate was 1.8%. 704 people lived in owner-occupied housing units and 450 people lived in rental housing units. As of the census of 2000, there were 1,111 people, 404 households, 302 families residing in the city; the population density was 739.7 people per square mile. There were 460 housing units at an average density of 306.3 per square mile. The racial makeup of the city was 85.87% White, 1.98% Native American, 0.45% Asian, 8.91% from other races, 2.79% from two or more races.
13.50% of the population were Hispanic or Latino of any race. There were 404 households out of which 34.2% had children under the age of 18 living with them, 59.2% were married couples living together, 11.1% had a female householder with no husband present, 25.2% were non-families. 23.5% of all households were made up of individuals and 9.2% had someone living alone, 65 years of age or older. The average household size was 2.75 and the average family size was 3.22. In the city, the population was spread out with 29.8% under the age of 18, 7.0% from 18 to 24, 25.8% from 25 to 44, 26.1% from 45 to 64, 11.3% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 111.6 males. For every 100 females age 18 and over, there were 105.3 males. The median income for a household in the city was $27,917, the median income for a family was $31,761. Males had a median income of $31,161 versus $23,333 for females; the per capita income for the city was $15,692. About 15.6% of families and 21.3% of the population were below the poverty line, including 27.2% of those under age 18 and 4.5% of those age 65 or over.
Maricopa Fire Department was established in 1910 with Chief F. W. Ball serving as the first fire chief. Maricopa Hospital opened on April 22, 1911 and the city was incorporated on July 25, 1911. Gary Biggerstaff was the chief of police when budget problems forced the city to close its police department in 1998; the Kern County Sheriff's Department provided police services to the citizens of Maricopa from 1998 until 2006 when the city reopened its police department in the old building. As reported in the Los Angeles Times on July 4, 2011, the Maricopa Police Department has become embroiled in a local controversy playing out through large signs posted on the city's main thoroughfare; the police have been accused of racial profiling and "over-enforcement" regarding traffic violations and frequent towing of vehicles driven by drivers without proof of insurance or with license or license plate infractions. In mid-2011, American Civil Liberties Union lawyer Jennie Pasquarella is quoted as saying, "Maricopa has been a shining example of impoundments gone wrong," and "They're creating a racket to steal people's cars."Police Chief Derek Merritt and other city officials have
Arvin is a city in Kern County, California. Arvin is located 15 miles southeast at an elevation of 449 feet; as of the 2010 census, the population was 19,304, up from 12,956 at the 2000 census. In 2007, the United States Environmental Protection Agency listed Arvin as having the highest levels of smog of any community in the United States; the city's level of ozone, smog's primary component, exceeded the EPA's acceptable limits an average of 73 days per year between 2004 and 2006. Wired telephone numbers in Arvin follow the format 854-xxxx or 855-xxxx and the ZIP Code is 93203. Property sales of lots in present-day Arvin began in 1906; the Arvin Post Office was established in 1914 and the community incorporated as a city in 1960. The city was named after Arvin Richardson, the son of one of the original settling families from San Bernardino. Birdie Heard petitioned for the addition of the post office in 1914 and submitted proposed names including Bear Mountain and Arvin. Officials in Washington D.
C. chose Arvin as it was the only proposed name, not in use in California. Birdie was the city's first postmaster, she set up the post office in her living room but it was moved to the general store owned by the Staples family. The in-store post office was the area's first informal library until an official branch of the Kern County Library system was established in 1927; the Mountain View Oil Field, which underlies the town and much of the surrounding area, was discovered in 1933 and developed extensively in the 1930s. Many oil wells still surround the town; the Arvin Tiller started publication in 1939 and Arvin High School was built in 1949. The city was nearly destroyed on July 1952 during the M7.3 Kern County earthquake. Arvin suffered further damage on December 1977, when a dust storm hit the area; the Arvin Migratory Labor Camp was the first federally operated farm labor camp opened by the Farm Security Administration in 1937, one of many New Deal programs created during the presidency of Franklin D. Roosevelt to respond to the Great Depression.
This agricultural camp was considered a model, was built by the Resettlement Administration. According to the United States Census Bureau, the city has a total area of 4.9 square miles, all of it land. According to the Köppen Climate Classification system, Arvin has a semi-arid climate, abbreviated "BSk" on climate maps; the economy of Arvin is based on agriculture, as such the employment statistics show seasonal variation. In March 2011, 41.9 percent of Arvin's residents were out of work, the highest of any city in Kern County. The 2010 United States Census reported that Arvin had a population of 19,304; the population density was 4,005.5 people per square mile. The racial makeup of Arvin was 10,247 White, 192 African American, 240 Native American, 155 Asian, 6 Pacific Islander, 7,655 from other races, 809 from two or more races. Hispanic or Latino of any race were 17,892 persons; the Census reported that 18,955 people lived in households, 281 lived in non-institutionalized group quarters, 68 were institutionalized.
There were 4,228 households, out of which 3,024 had children under the age of 18 living in them, 2,803 were opposite-sex married couples living together, 646 had a female householder with no husband present, 355 had a male householder with no wife present. There were 291 unmarried opposite-sex partnerships, 24 same-sex married couples or partnerships. 303 households were made up of individuals and 125 had someone living alone, 65 years of age or older. The average household size was 4.48. There were 3,804 families; the population was spread out with 7,422 people under the age of 18, 2,539 people aged 18 to 24, 5,399 people aged 25 to 44, 2,958 people aged 45 to 64, 986 people who were 65 years of age or older. The median age was 24.0 years. For every 100 females, there were 108.2 males. For every 100 females age 18 and over, there were 109.5 males. There were 4,476 housing units at an average density of 928.8 per square mile, of which 2,261 were owner-occupied, 1,967 were occupied by renters. The homeowner vacancy rate was 2.5%.
10,487 people lived in owner-occupied housing units and 8,468 people lived in rental housing units. As of the census of 2000, there were 12,956 people, 3,010 households, 2,645 families residing in the city; the population density was 2,695.9 people per square mile. There were 3,145 housing units at an average density of 654.4 per square mile. The racial makeup of the city was 45.04% White, 1.08% Black or African American, 1.46% Native American, 1.10% Asian, 0.12% Pacific Islander, 46.55% from other races, 4.65% from two or more races. 87.53% of the population were Hispanic or Latino of any race. There were 3,010 households out of which 63.2% had children under the age of 18 living with them, 67.7% were married couples living together, 13.7% had a female householder with no husband present, 12.1% were non-families. 9.5% of all households were made up of individuals and 5.4% had someone living alone, 65 years of age or older. The average household size was 4.28 and the average family size was 4.51.
In the city, the population was spread out with 40.0% under the age of 18, 12.8% from 18 to 24, 28.8% from 25 to 44, 12.5%
A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is used in Canada, Romania and the United States. County towns have a similar function in the United Kingdom and Republic of Ireland, in Jamaica. In most of the United States, counties are the political subdivisions of a state; the city, town, or populated place that houses county government is known as the seat of its respective county. The county legislature, county courthouse, sheriff's department headquarters, hall of records and correctional facility are located in the county seat though some functions may be located or conducted in other parts of the county if it is geographically large. A county seat is but not always, an incorporated municipality; the exceptions include the county seats of counties that have no incorporated municipalities within their borders, such as Arlington County, Virginia. Ellicott City, the county seat of Howard County, is the largest unincorporated county seat in the United States, followed by Towson, the county seat of Baltimore County, Maryland.
Some county seats may not be incorporated in their own right, but are located within incorporated municipalities. For example, Cape May Court House, New Jersey, though unincorporated, is a section of Middle Township, an incorporated municipality. In some of the colonial states, county seats include or included "Court House" as part of their name. In the Canadian provinces of Prince Edward Island, New Brunswick, Nova Scotia, the term "shire town" is used in place of county seat. County seats in Taiwan are the administrative centers of the counties. There are 13 county seats in Taiwan, which are in the forms of county-administered city, urban township or rural township. Most counties have only one county seat. However, some counties in Alabama, Georgia, Kentucky, Mississippi, New Hampshire, New York, Vermont have two or more county seats located on opposite sides of the county. An example is Harrison County, which lists both Biloxi and Gulfport as county seats; the practice of multiple county seat towns dates from the days.
There have been few efforts to eliminate the two-seat arrangement, since a county seat is a source of pride for the towns involved. There are 36 counties with multiple county seats in 11 states: Coffee County, Alabama St. Clair County, Alabama Arkansas County, Arkansas Carroll County, Arkansas Clay County, Arkansas Craighead County, Arkansas Franklin County, Arkansas Logan County, Arkansas Mississippi County, Arkansas Prairie County, Arkansas Sebastian County, Arkansas Yell County, Arkansas Columbia County, Georgia Lee County, Iowa Campbell County, Kentucky Kenton County, Kentucky Essex County, Massachusetts Middlesex County, Massachusetts Plymouth County, Massachusetts Bolivar County, Mississippi Carroll County, Mississippi Chickasaw County, Mississippi Harrison County, Mississippi Hinds County, Mississippi Jasper County, Mississippi Jones County, Mississippi Panola County, Mississippi Tallahatchie County, Mississippi Yalobusha County, Mississippi Jackson County, Missouri Hillsborough County, New Hampshire Seneca County, New York Bennington County, Vermont In New England, the town, not the county, is the primary division of local government.
Counties in this region have served as dividing lines for the states' judicial systems. Connecticut and Rhode Island have no county level of thus no county seats. In Vermont and Maine the county seats are designated shire towns. County government consists only of a Superior Court and Sheriff, both located in the respective shire town. Bennington County has two shire towns. In Massachusetts, most government functions which would otherwise be performed by county governments in other states are performed by town or city governments; as such, Massachusetts has dissolved many of its county governments, the state government now operates the registries of deeds and sheriff's offices in those counties. In Virginia, a county seat may be an independent city surrounded by, but not part of, the county of which it is the administrative center. Two counties in South Dakota have their county seat and government services centered in a neighboring county, their county-level services are provided by Fall River Tripp County, respectively.
In Louisiana, divided into parishes rather than counties, county seats are referred to as parish seats. Alaska is divided into boroughs rather than counties; the Unorganized Borough, which covers 49 % of Alaska's area, has equivalent. The state with the most counties is Texas, with 254, the state with the fewest counties is Delaware, with 3. County seat war Administrative center County town, administrative centres in Ireland and the UK Chef-lieu, administrative centres in Algeria, Luxembourg, France and Tunisia Municipality, equivalent to county in many c
Race and ethnicity in the United States Census
Race and ethnicity in the United States Census, defined by the federal Office of Management and Budget and the United States Census Bureau, are self-identification data items in which residents choose the race or races with which they most identify, indicate whether or not they are of Hispanic or Latino origin. The racial categories represent a social-political construct for the race or races that respondents consider themselves to be and, "generally reflect a social definition of race recognized in this country." OMB defines the concept of race as outlined for the US Census as not "scientific or anthropological" and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference." The race categories include both national-origin groups. Race and ethnicity are considered separate and distinct identities, with Hispanic or Latino origin asked as a separate question. Thus, in addition to their race or races, all respondents are categorized by membership in one of two ethnic categories, which are "Hispanic or Latino" and "Not Hispanic or Latino".
However, the practice of separating "race" and "ethnicity" as different categories has been criticized both by the American Anthropological Association and members of US Commission on Civil Rights. In 1997, OMB issued a Federal Register notice regarding revisions to the standards for the classification of federal data on race and ethnicity. OMB developed race and ethnic standards in order to provide "consistent data on race and ethnicity throughout the Federal Government; the development of the data standards stem in large measure from new responsibilities to enforce civil rights laws." Among the changes, OMB issued the instruction to "mark one or more races" after noting evidence of increasing numbers of interracial children and wanting to capture the diversity in a measurable way and having received requests by people who wanted to be able to acknowledge their or their children's full ancestry rather than identifying with only one group. Prior to this decision, the Census and other government data collections asked people to report only one race.
The OMB states, "many federal programs are put into effect based on the race data obtained from the decennial census. Race data are critical for the basic research behind many policy decisions. States require these data to meet legislative redistricting requirements; the data are needed to monitor compliance with the Voting Rights Act by local jurisdictions". "Data on ethnic groups are important for putting into effect a number of federal statutes. Data on Ethnic Groups are needed by local governments to run programs and meet legislative requirements." The 1790 United States Census was the first census in the history of the United States. The population of the United States was recorded as 3,929,214 as of Census Day, August 2, 1790, as mandated by Article I, Section 2 of the United States Constitution and applicable laws."The law required that every household be visited, that completed census schedules be posted in'two of the most public places within, there to remain for the inspection of all concerned...' and that'the aggregate amount of each description of persons' for every district be transmitted to the president."
This law along with U. S. marshals were responsible for governing the census. One third of the original census data has been lost or destroyed since documentation; the data was lost in 1790–1830 time period and included data from: Connecticut, Maryland, New Hampshire, New York, North Carolina, Rhode Island, South Carolina, Delaware, New Jersey, Virginia. Census data included the name of the head of the family and categorized inhabitants as follows: free white males at least 16 years of age, free white males under 16 years of age, free white females, all other free persons, slaves. Thomas Jefferson the Secretary of State, directed marshals to collect data from all thirteen states, from the Southwest Territory; the census was not conducted in Vermont until 1791, after that state's admission to the Union as the 14th state on March 4 of that year. There was some doubt surrounding the numbers, President George Washington and Thomas Jefferson maintained the population was undercounted; the potential reasons Washington and Jefferson may have thought this could be refusal to participate, poor public transportation and roads, spread out population, restraints of current technology.
No microdata from the 1790 population census is available, but aggregate data for small areas and their compatible cartographic boundary files, can be downloaded from the National Historical Geographic Information System. In 1800 and 1810, the age question regarding free white males was more detailed; the 1820
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti