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Steven A. Camarota is the director of research at the Center for Immigration Studies.

A new analysis of government data from December 2015 indicates that more than 61 million immigrants and their American-born children under age 18 now live in the United States; roughly three-fourths (45.3 million) are legal immigrants and their children. While the national debate has focused on illegal immigration, the enormous impact of immigration is largely the result of those brought in legally. These numbers raise profound questions that are seldom asked: What number of immigrants can be assimilated? What is the absorption capacity of our nation's schools, health care system, infrastructure, and, perhaps most importantly, its labor market? What is the impact on the environment and quality of life from significantly increasing the nation's population size and density? With some 45 million legal immigrants and their young children already here, should we continue to admit a million new legal permanent immigrants every year?

Among the findings of this analysis:

In December 2015 there were 61 million immigrants (legal and illegal) and U.S.-born children under age 18 with at least one immigrant parent living in the United States.

Immigrants allowed into the country legally and their children account for three-fourths (45.3 million) of all immigrants and their children.

Almost one in five U.S. residents is now an immigrant or minor child of an immigrant parent.

The numbers represent a complete break with the recent history of the United States. As recently as 1970, there were only 13.5 million immigrants and their young children in the country, accounting for one in 15 U.S. residents.

Just since 2000, the number of immigrants and their children has increased by 18.4 million.

The number of immigrants and their young children grew six times faster than the nation's total population from 1970 to 2015 — 353 percent vs. 59 percent.

In many states the increase in the number of immigrants and their minor children from 1970 to 2015 has been nothing short of astonishing: In Georgia, this population grew 3,058 percent (from 55,000 to 1.75 million), 25 times faster than the overall state population. In Nevada, this population grew 3,002 percent (from 26,000 to 821,000), six times faster than the overall state population. In North Carolina, this population grew 2,937 percent (from 47,000 to 1.43 million), 30 times faster than the overall state population. In Arkansas, this population grew 1,831 percent (from 12,000 to 228,000), 34 times faster than the overall state population. In Tennessee, this population grew 1,823 percent (from 28,000 to 537,000), 27 times faster than the overall state population. In Virginia, this population grew 1,150 percent (from 114,000 to 1.42 million), 15 times faster than the overall state population. In Oklahoma, this population grew 1,139 percent (from 37,000 to 458,000), 22 times faster than the overall state population. In Texas, this population grew 1,084 percent (from 582,000 to 6.89 million), 7 times faster than the overall state population. In Arizona, this population grew 1,019 percent (from 131,000 to 1.46 million), four times faster than the overall state population.



Data and Methods

Immigrants and Their Children in 2015. To estimate the size of the immigrant population (legal and illegal) in December 2015, we use the Current Population Survey (CPS) collected by the Census Bureau each month for the Bureau of Labor Statistics. The public-use file of the CPS from December 2015 shows 42.628 million immigrants (referred to as the foreign-born by the Census Bureau) in the United States.1 The December 2015 survey also shows 16.255 million children under age 18 with at least one foreign-born parent, for a total of 58.883 million immigrants and their minor children in the country.2

While the monthly CPS is the nation's primary source of information on the nation's labor force, it does not fully capture the foreign-born population. The yearly American Community Survey (ACS) is a much larger survey with somewhat better coverage of the population than the CPS.3 The ACS is weighted to reflect the entire U.S. population in July of each year. Unfortunately, the ACS is only released once a year, typically in the October following the calendar year of the survey; so data for 2015 will not be available for many months. The ACS also does not ask about parents' place of birth, so it is not possible to use the survey to directly measure the number of children with immigrant parents. In contrast, the CPS is usually released only a few days or weeks after it is collected. In recent years the ACS has shown an immigrant population that is 4.5 percent larger than in the CPS.4 The U.S.-born population in recent years has averaged 1.34 percent larger in the ACS than in the CPS.5

If we adjust upward the December 2015 CPS to reflect the ACS, there were a total of 61.02 million immigrants and their minor children in the United States at the end of 2015.6 This equals 18.9 percent of the nation's total population, or roughly one out of every five U.S. residents in December of last year. It may be worth noting that if we do not adjust the December 2015 CPS to reflect the ACS, then immigrants and their minor children are 18.6 percent of the population.

While there remains significant undercount of immigrants in the ACS, we do not adjust for the undercount of immigrants in Census data. Instead, we simply adjust the CPS to reflect the ACS. This allows us to compare figures for December 2015 with Census Bureau data from 2000 and 1970, both of which are also not adjusted for undercount. Nonetheless, the Department of Homeland Security has estimated that 1.85 million immigrants are missed in the ACS.7 Thus it is likely that the actual number of immigrants and their children is closer to 63 million.

Immigrants and Their Children in 2000. The ACS was not fully implemented in 2000, so to estimate the number of immigrants we use the 2000 Census. The 2000 Census was the last census to identify the foreign-born — the 2010 Census did not include this question. The 2000 Census showed 31.108 million immigrants in the country. But the 2000 Census did not include a question on the birthplace of parents, so it is necessary to use the CPS from 2000 to estimate the number of children with immigrant parents.8 In total, there were 42.580 million immigrants and their children under age 18 in the country in 2000. 9

Immigrants and Their Children in 1970. The 1970 Census was the last census to ask about parents' place of birth. We use it to estimate the number of immigrants and their children in that year. Since the CPS did not include questions on parents' place of birth until 1994, and the 1980 and 1990 censuses also did not include the question, there is no straightforward way to estimate the number of immigrants and their children in 1980 or 1990. The 1970 Census shows 13.462 million immigrants and U.S.-born children under age 18 with at least one immigrant parent in the country.

Illegal Immigrants and Their Children. Almost all estimates of the illegal immigrant population in the United States are based on Census Bureau data, typically the ACS or CPS. Using the ACS, the Center for Migration Studies (CMS) recently estimated 10.9 million illegal immigrants in the country in 2014. CMS assumes an undercount in Census Bureau data of 7.5 percent, implying 10.1 million illegal immigrants in Census Bureau data in 2014.10 The Pew Research Center also bases its estimates on Census Bureau data and estimates an illegal immigrant population of 11.3 million in 2014.11 It is not entirely clear what undercount adjustment Pew used for their 2014 estimate. But they do state in prior analyses that through 2012 the undercount was 5 to 7 percent, implying that about 10.6 million illegal immigrants are in the 2014 data.12 The Department of Homeland Security 2012 estimate of illegal immigrants, the most recent it has published, shows a total illegal population of 11.43 million in 2012, with 1.14 million illegal immigrants missed by the ACS, implying an illegal population of 10.3 million in the data.13 Unless there was a dramatic growth in the illegal population in the last few years, there must be 10 to 11 million illegal immigrants in the December 2015 CPS after adjusting to reflect the ACS. In the discussion that follows, we assume 10.6 million are in the data.

The Pew Research Center has estimated that in 2012 there were 4.5 million U.S.-born children under age 18 living with an illegal immigrant parent.14 Although most researchers think the illegal population has been roughly stable in the last few years, the number of children of illegals has grown. While fertility has fallen significantly among foreign-born Hispanics, there were still roughly 900,000 births from 2012 to 2015 among illegal immigrants in the United States.15 However, births to illegal immigrants are offset each year by a small number of deaths, those who leave the country with their illegal immigrant parents, those who turn 18 each year, and those whose parents are awarded legal status.16

Our best estimate is that in 2015 there were 5.1 million children with at least one illegal immigrant parent. Taken together, the best available evidence indicates that there were a total of 15.7 million illegal immigrants and their U.S.-born children in the adjusted December 2015 CPS, accounting for 25.7 percent of the 61 million immigrants and their children in the country. This also means that there are 45.3 million legal immigrants and their U.S.-born children under age 18 in the country. While there is always some error when estimating illegal immigration, there is no question that about three-quarters of immigrants and their young children in the country in December 2015 are either legal immigrants or the minor children of legal immigrants.

End Notes

1 The foreign-born are those who were not U.S.-citizens at birth and include naturalized citizens, legal permanent residents, long-term temporary visitors (e.g. guestworkers and foreign students), and illegal immigrants.

2 If we exclude those with only a foreign-born mother it would reduce the number by 4 percent, to 56.519 million immigrants and their minor children.

3 One important difference between the surveys is that the ACS includes those in institutions (e.g. prisons and nursing homes) and the CPS does not. While the two surveys generally track each other, the CPS shows a somewhat smaller population, reflecting the different nature of the two surveys.

4 The ACS reflects the U.S. population on July 1 of the year in which it was conducted. The ACS from 2013 shows 41,341 million immigrants. The July 2013 CPS shows 39.653 million immigrants. The 2014 ACS shows 42.236 million immigrants and the CPS for July 2014 shows 40.322 million. The difference between ACS and CPS in the last two years averages 4.5 percent.

5 The ACS reflects the U.S. population on July 1 of the year in which it was conducted. The ACS from 2013 shows 274.788 million natives. The July 2013 CPS shows 271.292 million natives. The 2014 ACS shows 276.621 million natives and the CPS for July 2014 shows 272.830 million. The difference between the ACS and CPS in the last two years averages 1.34 percent for the native-born.

6 The calculation is as follows: The foreign-born population from the December 2015 CPS of 42.628 million is multiplied by 1.045 and the native population of 274.448 from the December CPS is multiplied by 1.0134. The native-born population in the December CPS includes the 16.255 million children with at least one immigrant parent. These adjustments create an immigrant population of 44.547 million and a total native population of 278.123 million. The number of immigrants and their minor children in December 2015 stood at 61.02 million, 16.473 million of whom were U.S.-born children under age 18 with an immigrant parent. Using this approach, the total population of the country was 322.67 million at the end of last year. This population almost exactly matches the monthly population estimate provided by the Census Bureau early this year for December 2015.

7 Bryan Baker and Nancy Rytin, "Estimates of the Unauthorized Immigrant Population Residing in the United States: January 2012", Department of Homeland Security, March 2013. Table 2 shows a 1.85 million undercount among post-1980 immigrants in the 2011 ACS, with 190,000 non-immigrants visa holders, 520,000 legally resident immigrants, and 1.14 million unauthorized immigrants omitted.

8 We use the Annual Social and Economic Supplement of the CPS, referred to as the CPS ASES and collected in March, to estimate the number of U.S.-born children of immigrants. As the decennial census reflects the population on April 1,, the two data sources together should provide a good estimate of the number of immigrants and their children in the first part of 2000.

9 Using the same approach for 2010 (except substituting the ACS for the census) shows 55.125 million immigrants and their young children; this means the growth 2000 to 2010 was 12.545 million, and from 2010 to 2015 it was 5.894 million.

10 Robert Warren, "US Undocumented Population Drops Below 11 Million in 2014, with Continued Declines in the Mexican Undocumented Population", Journal on Migration and Human Security, Center for Migration Studies, 2015.

11 Jeffrey Passel and D'Vera Cohn, "Unauthorized immigrant population stable for half a decade", Pew Research Center, September 11, 2015.

12 Jeffrey Passel, D'Vera Cohn, and Ana Gonzalez-Barrera, "Population Decline of Unauthorized Immigrants Stalls, May Have Reversed", Pew Research Center, September 23, 2013.

13 Bryan Baker and Nancy Rytin, "Estimates of the Unauthorized Immigrant Population Residing in the United States: January 2012", Department of Homeland Security, March 2013.

14 Jeffrey S. Passel and D'Vera Cohn, "Number of babies born in U.S. to unauthorized immigrants declines", Pew Research Center, September 11, 2015.

15 Steven Camarota and Karen Ziegler, "The Declining Fertility of Immigrants and Natives", Center for Immigration Studies, March 2015.

16 Robert and John R. Warren estimate that from 2000 to 2009 one million illegal immigrants living in the United States received legal status (green cards). This includes those who returned to their home countries to get their green cards. See Table 3 of their February 2013 article in International Migration Review, "Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010".