Per capita income
Per capita income or average income measures the average income earned per person in a given area in a specified year. It is calculated by dividing the area's total income by its total population. Per capita income is national income divided by population size. Per capita income is used to measure an area's average income and compare the wealth of different populations. Per capita income is used to measure a country's standard of living, it is expressed in terms of a used international currency such as the euro or United States dollar, is useful because it is known, is calculable from available gross domestic product and population estimates, produces a useful statistic for comparison of wealth between sovereign territories. This helps to ascertain a country's development status, it is one of the three measures for calculating the Human Development Index of a country. In the United States, it is defined by the U. S. Census Bureau as the following: "Per capita income is the mean money income received in the past 12 months computed for every man and child in a geographic area."
Critics claim that per capita income has several weaknesses in measuring prosperity: Comparisons of per capita income over time need to consider inflation. Without adjusting for inflation, figures tend to overstate the effects of economic growth. International comparisons can be distorted by cost of living differences not reflected in exchange rates. Where the objective is to compare living standards between countries, adjusting for differences in purchasing power parity will more reflect what people are able to buy with their money, it does not reflect income distribution. If a country's income distribution is skewed, a small wealthy class can increase per capita income while the majority of the population has no change in income. In this respect, median income is more useful when measuring of prosperity than per capita income, as it is less influenced by outliers. Non-monetary activity, such as barter or services provided within the family, is not counted; the importance of these services varies among economies.
Per capita income does not consider whether income is invested in factors to improve the area's development, such as health, education, or infrastructure. List of countries by average wage List of countries by GDP per capita—GDP at market or government official exchange rates per inhabitant List of countries by GDP per capita—GDP calculated at purchasing power parity exchange per inhabitant List of countries by GNI per capita List of countries by GNI per capita List of countries by income equality Total personal income
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
San Gabriel Valley
The San Gabriel Valley is one of the principal valleys of Southern California, lying to the east of the city of Los Angeles. Surrounding features include: San Gabriel Mountains on the north, San Rafael Hills to the west, with Los Angeles Basin beyond; the valley derives its name from the San Gabriel River that flows southward through the center of the valley, which itself was named for the Spanish Mission San Gabriel Arcángel built in the Whittier Narrows in 1771. At one time predominantly agricultural, the San Gabriel Valley is today entirely urbanized and is an integral part of the Greater Los Angeles metropolitan area, it is one of the most ethnically diverse regions in the country. About 200 square miles in size, the valley includes thirty-one cities and five unincorporated communities. In 1886, Pasadena was the first independent incorporated city still located in Los Angeles County; the San Gabriel Valley is in Los Angeles County. The incorporated cities and unincorporated neighborhoods of the San Gabriel Valley include: Whittier, like Montebello, is considered both a San Gabriel Valley city and part of the Gateway Cities region.
An unincorporated portion of Whittier, Rose Hills, sits below the Puente Hills. Although these hills are small compared to the San Gabriel Mountains, the fact that most of the city sits around them makes Whittier a San Gabriel Valley city; this is similar to Montebello, a member of the Gateway Cities Council of Governments, despite geographically being part of the San Gabriel Valley. Claremont, Diamond Bar, La Verne, San Dimas and Walnut are adjacent to the San Gabriel Valley, although are properly considered part of the Pomona Valley, they are commonly considered part of the San Gabriel Valley; the 57 Freeway is considered the dividing line between the Pomona and San Gabriel valleys. However, for statistical and economic development purposes, the County of Los Angeles includes these six cities as part of the San Gabriel Valley; the community of El Sereno, in the city of Los Angeles, is situated at the westernmost edge of the Valley. Unofficial estimates place the combined population of the San Gabriel Valley at around 2 million—roughly a fifth of the population of Los Angeles County.
Before the arrival of the Spaniards, the land along the Rio Hondo River, a branch of the San Gabriel River, was populated by the Tongva part of the Uto-Aztecan family Native Americans. The Tongva occupied much of the Los Angeles basin and the islands of Santa Catalina, San Nicolas, San Clemente and Santa Barbara. In the northern part of the valley were the Hahanog-na Indian tribe, a branch of the Tongva Nation who lived in villages scattered along the Arroyo Seco and the canyons from the mountains down to the South Pasadena area. In 1542, when the explorer Juan Rodriguez Cabrillo arrived off the shores of San Pedro and Santa Catalina; the Tongva were the people. The language of the Tongva was different from the neighboring Indian tribes and it was called Gabrielino by the Spanish; the Tongva provide the origin of many current names. The Gabrielinos lived in dome-like structures with thatched exteriors. Both sexes tattooed their bodies. During warm weather the men wore little clothing, but the women would wear minimal skirts made of animal hides.
During the cold weather they would wear animal skin capes. European diseases killed many of the Tongva and by 1870 the area had few remaining native inhabitants. Today, several bands of Tongva people live in the Los Angeles area; the first Europeans to see inland areas of California were the members of the 1769 Portolà expedition, which traveled north by land after establishing the first Spanish settlement in today's state of California at San Diego. On July 30, the expedition crossed the San Gabriel River and continued north toward what is now the city of Los Angeles. To cross the river, the expedition built a rough bridge, which gave the name La Puente to today's San Gabriel Valley city, hills to the south are called the Puente Hills. A few years a mission was established near the river crossing. Mission San Gabriel Arcangel was founded by Franciscan Father Junipero Serra, first head of the Spanish missions in California, on September 8, 1771, its original location was near where San Gabriel Boulevard now crosses the Rio Hondo, near the present day Juan Matias Sanchez Adobe.
Angel Somera and Pedro Cambon were the first missionary priests at the new mission, which marked the beginning of the Los Angeles region's settlement by Spaniards. The San Gabriel mission was the third of twenty-one missions that would be established along California's El Camino Real; the San Gabriel mission did well in establishing cattle ranching and farming, but six years after its founding a destructive flood led the mission fathers to relocate the establishment to its current location farther north in present-day city of San Gabriel. The original mission site is now marked by a California Historical Landmark. During the early years of the mission, the region operated under a Rancho system; the lands which now compose the city of Montebello were parts of Rancho San Antonio, Rancho La Merced, Rancho Paso de Bartolo. The Juan Matias Sanchez Adobe, built in 1844, remains standin
California State Route 60
State Route 60 is an east-west state highway in the U. S. state of California. It runs from the East Los Angeles Interchange near downtown Los Angeles to an interchange with Interstate 10 in Beaumont; the highway serves the cities and communities on the eastern side of the Los Angeles metropolitan area and runs along the south side of the San Gabriel Valley. The highway provides a route across several spurs of the Peninsular Ranges, linking the Los Angeles Basin with the Pomona Valley and San Gabriel Valley, it runs from the East Los Angeles Interchange near the Los Angeles River in Los Angeles with Interstate 5, Interstate 10 and U. S. Route 101 east to I-10 in Riverside County, with overlaps at State Route 57 and Interstate 215; the highway runs parallel to Interstate 10, functioning as a bypass alternate east-west route through the area. SR 60 begins at the East Los Angeles Interchange near downtown Los Angeles, designated as the Pomona Freeway; the freeway heads east from the junction after splitting off from the Santa Monica Freeway and passes through East Los Angeles, intersecting the Long Beach Freeway.
Continuing east through the southern San Gabriel Valley, SR 60 passes through many cities and communities, intersecting the San Gabriel River Freeway in the City of Industry. It proceeds to an overlap with the Orange Freeway in Diamond Bar, right on the edge of the San Gabriel Valley. A short overlap carries SR 60 traffic on the same roadway as SR 57; the two routes head northeast through an arm of the San Gabriel Valley. Continuing east, SR 60 intersects the Chino Valley Freeway in Pomona, the Ontario Freeway in Jurupa Valley, the Riverside Freeway in Riverside, California. A short overlap carries SR 60 traffic on the same roadway as I-215; the two routes head southeast. The freeway runs through communities further east in the Inland Empire. After passing through Moreno Valley, SR 60 runs through the rugged hill country to the east. After that, SR 60 downgrades to an expressway, has with several at-grade interchanges with local roads. In Beaumont, SR 60 ends and merges into the Christopher Columbus Transcontinental Highway.
SR 60 traverses Los Angeles, San Bernardino, Riverside Counties. As it passes through many of Los Angeles' east side suburbs in southern San Gabriel and Pomona Valleys, it is a major transportation corridor. For the majority of its length it is parallel to, south of, the San Bernardino Freeway, Interstate 10, parallel to, north of, the Riverside Freeway, California State Route 91. Traffic congestion is exacerbated by the rapid population growth and, residential and industrial development in the inland communities known informally as the Inland Empire. In particular, it has become clogged of late with shipping container-laden trucks travelling from the ports of Los Angeles and Long Beach to rail yards and warehouses in the Inland Empire; as a result of the rapid development of the Inland Empire since the 1980s, the Moreno Valley Freeway now suffers from severe traffic congestion. In the mid-2000s, the northwestern section, concurrently signed with Interstate 215 underwent significant construction to improve traffic flow, but it still suffers from heavy congestion.
The freeway is known as the Pomona Freeway from its western terminus to its junction with State Route 91 and Interstate 215 in Riverside, the Moreno Valley Freeway east of this interchange until its eastern terminus at its junction with Interstate 10. The route is part of the California Freeway and Expressway System, is part of the National Highway System, a network of highways that are considered essential to the country's economy and mobility by the Federal Highway Administration; the route takes its number from former US 60, which now begins near Brenda and terminates on the east coast at Virginia Beach, Virginia. Before 1964, US 60 ran from Los Angeles to the Arizona state line, where it continued its nationwide trek overlapping US 99 and US 70 along the way; the advent of I-10 created a situation where, at one point, four different signed routes would run along the state-maintained highway. In 1964, California implemented a plan to simplify its highway-numbering system, where one state highway had only one route number and concurrencies were sternly discouraged.
As a result, the US 60 designation was removed. I-10 superseded US 60's alignment from Beaumont and towards the Arizona state line though the routing was only a freeway; this left the designated Route 60 from Beaumont to Los Angeles orphaned from its original U. S. Highway; this new Route 60 was provisionally signed as a U. S. Highway since the designation would guide motorists from Los Angeles to Arizona in the absence of a completed freeway for I-10. S. Highway designation disappeared. At least one California highway sign managed to be overlooked for many years afterward. A sign on Hess Boulevard at SR 62 in the unincorporated town of Morongo Valley pointed not to I-10 but to US 60 stood through the early 2000s; the stretch of SR 60 along the Moreno Valley Freeway made national headlines in April 2004, when five-year-old Ruby Bustamante of Indio and her 26-year-old mother, were reported mi
Los Angeles County, California
Los Angeles County the County of Los Angeles, in the Los Angeles metropolitan area of the U. S. state of California, is the most populous county in the United States, with more than 10 million inhabitants as of 2017. As such, it is the largest non–state level government entity in the United States, its population is larger than that of 41 individual U. S. states. It is the third-largest metropolitan economy in the world, with a Nominal GDP of over $700 billion—larger than the GDPs of Belgium and Taiwan, it has 88 incorporated cities and many unincorporated areas and, at 4,083 square miles, it is larger than the combined areas of Delaware and Rhode Island. The county is home to more than one-quarter of California residents and is one of the most ethnically diverse counties in the U. S, its county seat, Los Angeles, is California's most populous city and the nation's second largest city with about 4 million people. Los Angeles County is one of the original counties of California, created at the time of statehood in 1850.
The county included parts of what are now Kern, San Bernardino, Inyo, Tulare and Orange counties. In 1851 and 1852, Los Angeles County stretched from the coast to the border of Nevada; as the population increased, sections were split off to organize San Bernardino County in 1853, Kern County in 1866, Orange County in 1889. Prior to the 1870s, Los Angeles County was divided into townships, many of which were amalgamations of one or more old ranchos, they were: Azusa El Monte Azusa and El Monte Townships were merged for the 1870 census. City of Los Angeles Los Angeles Township Los Nietos San Jose San Gabriel Santa Ana. For the 1870 census, Annaheim district was enumerated separately. San Juan. San Pedro. Tejon When Kern County was formed, the portion of the township remaining in Los Angeles County became Soledad Township According to the U. S. Census Bureau, the county has an area of 4,751 square miles, of which 4,058 square miles is land and 693 square miles is water. Los Angeles County borders 70 miles of coast on the Pacific Ocean and encompasses mountain ranges, forests, lakes and desert.
The Los Angeles River, Rio Hondo, the San Gabriel River and the Santa Clara River flow in Los Angeles County, while the primary mountain ranges are the Santa Monica Mountains and the San Gabriel Mountains. The western extent of the Mojave Desert begins in the Antelope Valley, in the northeastern part of the county. Most of the population of Los Angeles County is located in the south and southwest, with major population centers in the Los Angeles Basin, San Fernando Valley and San Gabriel Valley. Other population centers are found in the Santa Clarita Valley, Pomona Valley, Crescenta Valley and Antelope Valley; the county is divided west-to-east by the San Gabriel Mountains, which are part of the Transverse Ranges of southern California, are contained within the Angeles National Forest. Most of the county's highest peaks are in the San Gabriel Mountains, including Mount San Antonio 10,068 feet ) at the Los Angeles-San Bernardino county lines, Mount Baden-Powell 9,399 feet, Mount Burnham 8,997 feet and Mount Wilson 5,710 feet.
Several lower mountains are in the northern and southwestern parts of the county, including the San Emigdio Mountains, the southernmost part of Tehachapi Mountains and the Sierra Pelona Mountains. Los Angeles County includes San Clemente Island and Santa Catalina Island, which are part of the Channel Islands archipelago off the Pacific Coast. East: Eastside, San Gabriel Valley, portions of the Pomona Valley West: Westside, Beach Cities South: South Bay, South Los Angeles, Palos Verdes Peninsula, Gateway Cities, Los Angeles Harbor Region North: San Fernando Valley, Crescenta Valley, portions of the Conejo Valley, portions of the Antelope Valley and Santa Clarita Valley Central: Downtown Los Angeles, Mid-Wilshire, Northeast Los Angeles Angeles National Forest Los Padres National Forest Santa Monica Mountains National Recreation Area Los Angeles County had a population of 9,818,605 in the 2010 United States Census; the racial makeup of Los Angeles County was 4,936,599 White, 1,346,865 Asian, 856,874 African American, 72,828 Native A
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, sleet, snow and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates", thus and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate. Two processes acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called "showers."Moisture, lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. This process is active when freezing rain occurs. A stationary front is present near the area of freezing rain and serves as the foci for forcing and rising air.
Provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. The cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. Most precipitation is caused by convection; the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
Precipitation is a major component of the water cycle, is responsible for depositing the fresh water on the planet. 505,000 cubic kilometres of water falls as precipitation each year. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres, but over land it is only 715 millimetres. Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Precipitation may occur on other celestial bodies, e.g. when it gets cold, Mars has precipitation which most takes the form of frost, rather than rain or snow. Precipitation is a major component of the water cycle, is responsible for depositing most of the fresh water on the planet. 505,000 km3 of water falls as precipitation each year, 398,000 km3 of it over the oceans. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective and orographic rainfall.
Convective processes involve strong vertical motions that can cause the overturning of the atmosphere in that location within an hour and cause heavy precipitation, while stratiform processes involve weaker upward motions and less intense precipitation. Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice. Mixtures of different types of precipitation, including types in different categories, can fall simultaneously. Liquid forms of precipitation include drizzle. Rain or drizzle that freezes on contact within a subfreezing air mass is called "freezing rain" or "freezing drizzle". Frozen forms of precipitation include snow, ice needles, ice pellets and graupel; the dew point is the temperature to which a parcel must be cooled in order to become saturated, condenses to water. Water vapor begins to condense on condensation nuclei such as dust and salt in order to form clouds. An elevated portion of a frontal zone forces broad areas of lift, which form clouds decks such as altostratus or cirrostratus.
Stratus is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. It can form due to the lifting of advection fog during breezy conditions. There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling, evaporative cooling. Adiabatic cooling occurs when air expands; the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a colder surface by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath. Evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation; the main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet lan
A ZIP Code is a postal code used by the United States Postal Service in a system it introduced in 1963. The term ZIP is an acronym for Zone Improvement Plan; the basic format consists of five digits. An extended ZIP+4 code was introduced in 1983 which includes the five digits of the ZIP Code, followed by a hyphen and four additional digits that reference a more specific location; the term ZIP Code was registered as a servicemark by the U. S. Postal Service, but its registration has since expired; the early history and context of postal codes began with postal district/zone numbers. The United States Post Office Department implemented postal zones for numerous large cities in 1943. For example: The "16" was the number of the postal zone in the specific city. By the early 1960s, a more organized system was needed, non-mandatory five-digit ZIP Codes were introduced nationwide on July 1, 1963; the USPOD issued its Publication 59: Abbreviations for Use with ZIP Code on October 1, 1963, with the list of two-letter state abbreviations which are written with both letters capitalized.
An earlier list in June had proposed capitalized abbreviations ranging from two to five letters. According to Publication 59, the two-letter standard was "based on a maximum 23-position line, because this has been found to be the most universally acceptable line capacity basis for major addressing systems", which would be exceeded by a long city name combined with a multi-letter state abbreviation, such as "Sacramento, Calif." along with the ZIP Code. The abbreviations have remained unchanged, with the exception of Nebraska, changed from NB to NE in 1969 at the request of the Canadian postal administration, to avoid confusion with the Canadian province of New Brunswick. Robert Moon is considered the father of the ZIP Code; the post office only credits Moon with the first three digits of the ZIP Code, which describe the sectional center facility or "sec center." An SCF is a central mail processing facility with those three digits. The fourth and fifth digits, which give a more precise locale within the SCF, were proposed by Henry Bentley Hahn Sr.
The SCF sorts mail to all post offices with those first three digits in their ZIP Codes. The mail is sorted according to the final two digits of the ZIP Code and sent to the corresponding post offices in the early morning. Sectional centers do not deliver mail and are not open to the public, most of their employees work the night shift. Mail picked up at post offices is sent to their own SCF in the afternoon, where the mail is sorted overnight. In the case of large cities, the last two digits coincide with the older postal zone number thus: In 1967, these became mandatory for second- and third-class bulk mailers, the system was soon adopted generally; the United States Post Office used a cartoon character, which it called Mr. ZIP, to promote the use of the ZIP Code, he was depicted with a legend such as "USE ZIP CODE" in the selvage of panes of postage stamps or on the covers of booklet panes of stamps. In 1971 Elmira Star-Gazette reporter Dick Baumbach found out the White House was not using a ZIP Code on its envelopes.
Herb Klein, special assistant to President Nixon, responded by saying the next printing of envelopes would include the ZIP Code. In 1983, the U. S. Postal Service introduced an expanded ZIP Code system that it called ZIP+4 called "plus-four codes", "add-on codes", or "add-ons". A ZIP+4 Code uses the basic five-digit code plus four additional digits to identify a geographic segment within the five-digit delivery area, such as a city block, a group of apartments, an individual high-volume receiver of mail, a post office box, or any other unit that could use an extra identifier to aid in efficient mail sorting and delivery. However, initial attempts to promote universal use of the new format met with public resistance and today the plus-four code is not required. In general, mail is read by a multiline optical character reader that instantly determines the correct ZIP+4 Code from the address—along with the more specific delivery point—and sprays an Intelligent Mail barcode on the face of the mail piece that corresponds to 11 digits—nine for the ZIP+4 Code and two for the delivery point.
For Post Office Boxes, the general rule is. The add-on code is one of the following: the last four digits of the box number, zero plus the last three digits of the box number, or, if the box number consists of fewer than four digits, enough zeros are attached to the front of the box number to produce a four-digit number. However, there is no uniform rule, so the ZIP+4 Code must be looked up individually for each box; the ZIP Code is translated into an Intelligent Mail barcode, printed on the mailpiece to make it easier for automated machines to sort. A barcode can be printed by the sender, it is better to let the post office put one on. In general, the post office uses OCR technology, though in some cases a human might have to read and enter the address. Customers who send bulk mail can get a discount on postage if they have printed the barcode themselves and have presorted the mai