Illegal immigrant population of the United States
The actual size and the origin of the illegal immigrant population in the United States is uncertain and is difficult to ascertain because of difficulty in accurately counting individuals in this population. Figures from national surveys, administrative data and other sources of information vary widely. Two analyses by the Center for Immigration Studies of U.S. Census data estimate the illegal immigration population in 2015 ranged from 10.9 million to 15.7 million. The Pew Research Center indicates that there were 11.3 million undocumented immigrants in the U.S in 2014.
The "residual method" is widely used to estimate the unauthorized immigrant population of the USA. With this method, the known number of legally documented immigrants to the United States is subtracted from the reported U.S. Census number of self-proclaimed foreign born people (based on immigration records and adjusted by projections of deaths and out-migration) to obtain the total, unauthorized immigrant (residual) population. This methodology is used by the US Department of Homeland Security, the Pew Hispanic Center, the Center for Immigration Studies, and the US Census Bureau. Since unauthorized immigrants have many reasons for not answering the U.S. Census correctly and since there are no penalties for answering the U.S. Census incorrectly, it is accepted that it under-counts the number of undocumented immigrants. The users of this methodology assume that 10% of undocumented immigrants are not counted by census takers. The 10% assumption is based on a 2001 University of California survey asked of 829 people born in Mexico and living in Los Angeles whether they responded to census interviewers in the 2000 census with 40% of queried households refusing to answer the survey. Critics claim that the estimate is unreliable for a number of reasons: figures for outmigration are not tracked by the federal government; the proportion of undocumented immigrants who respond to the Census is unknown; the estimate that 10% of undocumented immigrants do not respond to the census is arbitrary and unsupported by a sufficient sample size and geographic spread; and that the self reporting of where one was born relies on the honesty of the person being questioned.
Using the residual methodology with a minimal 10% foreign born under-count correction (reason for correction size unstated) for the 2000 census, a 700,000 net undocumented immigrant increase/year assumption and data from the March 2004 Current Population Survey, Pew estimated that there were 10.3 million undocumented immigrants in the USA in 2004. Assuming the same rate of growth, Pew projected this population reached at least 11 million as of March 2005.
The Pew Hispanic Center estimates that, in the 1980s, the net advance of the U.S. undocumented immigrant population was at 130,000 per year, increasing to 450,000 per year from 1990 through 1994, further increasing to 750,000 per year from 1995 through 1999, and staying at 700,000–850,000+ per year since about 2000. Undocumented Mexican immigration amounts to about 500,000 per year of this influx since about 1999. According to the same Pew Hispanic Center study as of March 2005, the undocumented U.S. population had reached 11 million or more, including more than 6.5 million undocumented Mexicans, which is around 60% of all unauthorized immigrants. Assuming the same rate of growth as in recent years gives around 12 million undocumented immigrants in the United States as of January 2006, increasing at 700,000–850,000 per year—with undocumented Mexicans amounting to about 60%+ (7+ million) of the overall total by 2006. By September 2006, the undocumented immigrant U.S. population was thought to be around 13 million. About one-sixth of the undocumented immigrant population—about 1.7 million people as of 2005[update]—is under 18 years of age.
In 2006, legal immigrants to the United States numbered approximately 1,000,000 per year - of which about 600,000 were Change of Status immigrants who were already in the USA. Legal immigrants to the United States are now at their highest level ever at over 35,000,000. Net advances by undocumented immigrants into the USA have also soared from about 130,000 per year in the 1970s, to 300,000+ per year in the 1980s, to over 500,000 per year in the 1990s, to over 700,000 per year in the 2000s. Total entrance by unauthorized immigrants into the USA may have been as high as 1,500,000 per year in 2006 - with a net of at least 700,000 more unauthorized immigrants arriving each year to join the 12,000,000 to 20,000,000 that are already here in the USA 
Pulitzer prize winning investigative journalists Donald L. Barlett and James B. Steele estimated in Time magazine (in its September 12, 2004 issue) that the number of unauthorized immigrants entering into the USA that year would total 3 million based on Department of Homeland security estimates that only one out of four undocumented immigrants is apprehended at the border.
Bear Sterns' method
|Mexican Remittances and Illegal Population Growth|
|Non-Mex.||4.0 to 6.0|
|Total illegal aliens estimated by Bear Stearns||20.0 to 22.0 million**|
|Assumes the amount of remittances from the USA is proportional to the number of Mexicans living in the USA.
As can be seen the Pew and Bear Stern numbers are in basic agreement until around the year 2000.
Total remittances in 2005 were around $20 billion.
In 2005, Bear Stearns' investigators developed a different methodology to determine the number of undocumented immigrants in the United States. They made the assumption that the amount of remittances (money sent back to Mexico) is directly proportional to the number of Mexican immigrants in the United States. Other data used for their estimates are the increases of households and school enrollment in Mexican immigrant communities. They conclude that the number of undocumented immigrants in the United States may well be twice the official number put out by the U.S. Census of 9 million and may be 20 million people or higher. Information from The Mexican Central Bank details the remittances and shows their growth.
According to that data, remittances stayed fairly stable until 2000 when a steady and dramatic increase began. The change in remittances between 1997 and 1999 is most likely a problem in accounting – the three year average is still about 450 thousand/year consistent with other data. The agreement with the Pew estimate is reasonably good up to 2001 where there is a significant difference – just where the Pew and Census data becomes harder to extrapolate because of lack of good data. Using this technique Bear Sterns investigators come up with a possible undocumented population of 20 million or greater. (See figure for calculation) Other data confirming their estimates are the dramatic increases of households and school enrollment in Mexican immigrant communities (read their report for more details). Border Arrest data do not show this dramatic increase in apprehensions.
Impact of the global financial crisis of 2008–2009
The 2008 global financial crisis has had a large impact on America. The construction sector and other areas undocumented immigrants traditionally seek employment in have shrunk. The recession has also led to a surplus of American labor driving down the benefit of hiring undocumented immigrants. It is estimated that over a million undocumented immigrants have returned to Mexico since the beginning of the crisis.
In 2005, according to a Pew Hispanic Center report, there were 6.2 million undocumented immigrants from Mexico making 56 percent of immigrants present in the United States without documentation. 24 percent were from other Latin American countries; 9 percent were from Asia, 6 percent from Europe and Canada, and the remaining 4 percent from the rest of the world. In 2014, the Pew Hispanic Center estimated that the undocumented immigrant population from Mexico had reduced to 5.6 million or 49 percent of the undocumented immigrant population.
|Country of Origin (January 2006)|
|Latin & Central Amer.||3,000,000||24%|
|Europe + Canada||720,000||6%|
|Rest of World||480,000||4%|
The number of Mexican documented immigrants and Mexican undocumented immigrants in the United States has grown quite rapidly over the past 35 years, increasing almost 15-fold from about 760,000 in the 1970 Census to more than 11 million in 2004–an average annual growth rate of more than 8 percent, maintained over more than 3 decades. On average the net Mexican population, both documented and undocumented, living in the United States has grown by about 500,000 per year from 1995 to 2005 with 80 to 85 percent of the growth attributed to undocumented immigration.
- Record 61 million immigrants in U.S., 15.7 million illegally
- U.S. illegal immigrant population falls below 11 million, continuing nearly decade-long decline, report says
- Pew Research Center: "5 facts about illegal immigration in the U.S." By Jens Manuel Krogstad and Jeffrey S. Passel November 19, 2015
- Jeffrey S. Passel (June 2005). "Unauthorized Migrants: Numbers and Characteristics" (PDF). Pew Hispanic Center. p. 7.
- MICHAEL HOEFER; CHRISTOPHER CAMPBELL; NANCY RYTINA (January 2015). "Estimates of the Unauthorized Immigrant Population Residing in the United States: May 2006" (PDF). US Department of Homeland Security, Office of Immigration Statistics, Policy Directorate.
- Wall Street Journal: "In Counting Illegal Immigrants, Certain Assumptions Apply" by Carl Bialik May 7, 2010
- PEW 2005, p. 1
- Steven Malanga (Summer 2006). "How Unskilled Immigrants Hurt Our Economy".
- National Public Radio: "Gauging Illegal Immigration Numbers" May 05, 2006
- DONALD L. BARLETT; JAMES B. STEELE (September 20, 2004). "Who Left the Door Open?". Time. p. 5.
* Banco de Mexico
** Bear Stern's investigators
***PEW 2005[not in citation given]
- "CPSS-WB General Principles for International Remittances Services: The Point of View of Authorities: Banco de México" (PDF). The World Bank. May 2006.
- Preston, Julia (July 31, 2008). "Decline Seen in Numbers of People Here Illegally". The New York Times. Retrieved May 5, 2010.
- Pew Hispanic Center: "The Size and Characteristics of the Unauthorized Migrant Population in the U.S. - Estimates Based on the March 2005 Current Population Survey" by Jeffrey S. Passel March 7, 2006 |"The Mexican-born population in the United States, including both legal and unauthorized migrants, has grown by about 500,000 people a year for the past decade. Of the Mexican migrants in the U.S. less than 10 years, the Pew Hispanic Center estimates that approximately 80 to 85% are unauthorized"