Census Survey Shows Continued Rapid Growth in the Foreign-Born

Immigrant population (legal and illegal) grew 1.8 million in past year

By Steven A. Camarota and Karen Zeigler on November 23, 2021

An analysis of the Census Bureau’s monthly Current Population Survey (CPS) by the Center for Immigration Studies published last month showed that after falling for much of 2020, the foreign-born population (legal and illegal), rebounded dramatically through September of 2021. The newly released October data shows that this growth continued in October with the foreign-born population reaching 45.7 million — 246,000 more than last month and 1.8 million more than in October 2020. What makes these numbers important is that unlike arrival figures for legal immigrants or border apprehension numbers, the CPS provides insight into the number of foreign-born people, also referred to as immigrants, who have actually settled in the United States. The total immigrant population reflects both new arrivals as well as those who leave or die each year. As we pointed out before, there is a lot of variation from month to month in the CPS, so any change should be interpreted in light of this variability.

Growth in the Immigrant Population. While there is some undercount, particularly of illegal immigrants, the foreign-born in Census Bureau surveys includes all persons who were not U.S. citizens at birth — naturalized citizens, lawful permanent residents, long-term temporary visitors (e.g. guestworkers and foreign students), and illegal immigrants. Growth in the total immigrant population can only be caused by new legal and illegal immigrants arriving from abroad. Births to immigrants in the United States do not add to the foreign-born as all persons born in the United States are considered native-born by definition. New immigration is offset by those immigrants who leave the country each year (previously estimated at nearly one million annually) and natural mortality among the existing immigrant population of roughly 300,000 a year. For the immigrant population to grow, new arrivals must exceed return migration and deaths.

Figure 1 shows the total immigrant population (legal and illegal) from January 2010 to October 2021, along with margins of error. The figure shows that the nation’s immigrant population grew to 45.7 million in October 2021, a 1.8 million increase since October 2020. The growth in the last year follows a nearly 600,000 decline in the total immigrant population between October 2019 and October 2020. The decline almost certainly reflects the significant reduction in new legal and illegal immigration due to Covid-19 restrictions on international travel, the suspension, for a time, of visa processing at American consulates overseas, and Title 42 expulsions, which allowed the U.S. government to send illegal immigrants apprehended at the border immediately back to Mexico, even if the immigrant was not from that country. All of these factors seem to have significantly slowed the pace of new arrivals into the country. At the same time, some level of outmigration continued during this time period as did natural mortality, causing the total immigrant population to fall through the middle of 2020. 

Figure 2 shows a year-to-year monthly change in the size of the immigrant population. The impact of Covid-19 restrictions can clearly be seen starting in the first part of 2020. The biggest year-to-year monthly decline was the 1.6 million from March 2019 to March 2020. But the immigrant population fell to its smallest size of 43.8 million in August 2020. Figure 2 shows that the 1.759 million increase between October 2020 and October of this year is among the largest single year increases, but it is not the largest.  

Illegal Immigration. The federal government, as well as outside researchers, have previously estimated that nearly three-quarters of illegal immigrants are Hispanic, so the recent increase in Hispanic immigrants can be seen as an indication that illegal immigration has increased dramatically in the last year. Hispanic immigrants (legal and illegal), accounted for 1 million, or 58 percent, of the nearly 1.8 million increase since last October. Figure 3 shows the number of Hispanic immigrants living in the country and Figure 4 shows year-to-year monthly changes in that population. Like the overall foreign-born population, Figures 3 and 4 show that the number of Hispanic immigrants fell dramatically at the height of the Covid-19 epidemic before rebounding dramatically at the end of 2020 and into 2021. This strongly suggests that the dramatic surge in illegal immigration at the southern border since President Biden’s election is showing up, at least in part, in the monthly Current Population Survey.

The Trump Effect. As we discussed in more detail in our prior post, the monthly data also show evidence for a “Trump effect” on immigration — legal and illegal. This confirms our earlier analysis of other Census Bureau data showing that during his first three years in office, before Covid-19 hit, growth in the legal and illegal immigrant population slowed, reflecting a decline in new arrivals and a substantial increase in out-migration. The monthly data confirms our prior findings. In his four years in office (January 2017 to January 2021), the foreign-born population grew by 1.6 million, less than half the 3.4 million growth during Obama’s second term (January 2013 to January 2017). Focusing only on the first three years (January 2017 to January 2020) of Trump’s administration, before Covid, shows the immigrant population grew by one million, compared to three million in the first three years of the second Obama administration (January 2013 to January 2016).

About the Data. It must be remembered that the monthly CPS, while a large sample, still has a relatively large numerical margin of error of roughly ±500,000 for the foreign-born, assuming a 90 percent confidence level. So numerical fluctuations from month to month can be quite large, making it necessary to compare changes over longer periods of time when drawing conclusions about trends. The margins of error shown in Figures 1 and 3 are based on standard errors calculated using parameter estimates, which reflect the survey’s complex design. Neither the BLS or the Census Bureau has provided parameter estimates for the general population for the monthly CPS, so we use those for the labor force.

It should also be noted that, like virtually all modern surveys, the CPS is weighted to reflect the total population by age, race, sex, and Hispanic origin. Each January the weights used in the CPS, also called population controls, are re-adjusted to reflect updated figures on births, deaths, and net international migration. The weights are then carried forward for each month during the rest of the year. The update in January 2021 adjusted the size of the U.S. population slightly downward for January 2021 from December 2020, including the number of Hispanics and Asians. This should have reduced growth in the foreign-born slightly. Yet, the CPS still shows growth in the number of immigrants after this adjustment.

Potential Problems with the CPS. The Census Bureau collects the monthly CPS for the Bureau of Labor Statistics (BLS). The BLS reports potential problems with the CPS since March 2020 because of the Covid-19 pandemic. They state that response rates from March 2020 through October 2021 to the CPS were lower than prior to Covid-19, though rates have improved since hitting a low in June 2020. These lower rates increase the sampling error of the survey. It is not known if this problem had any specific impact on estimates of the foreign-born in the data. However, in June 2020, when the problem was most pronounced, BLS stated that “Although the response rate was adversely affected by pandemic-related issues, BLS was still able to obtain estimates that met our standards for accuracy and reliability.”

The Other Large Census Bureau Survey. The Census Bureau’s annual American Community Survey (ACS), which also identifies immigrants, is much larger than the CPS and is often used to study the foreign-born. Its larger size means that it has smaller margins of error than the CPS. But the ACS for 2020 has not been released and it provides annual estimates. Moreover, the ACS reflects the U.S. population in July of each year, so when the 2020 ACS is released, it should show a decline in the foreign-born between 2019 and 2020, as in the CPS. But the 2020 ACS will not reflect the rebound after July 2020. We also do not know how the Covid-19 epidemic affected collection of the 2020 ACS.