Legal & Unauthorized Immigration by the Numbers

by Ben Lorica (last updated Oct/2011)

Given the recent attention focused on unauthorized immigration to the US, I collected data from several sources and produced a few charts to place the topic in context. Discussions around this topic quickly get emotional and I'm hoping data can lead to calmer exchanges. I hope that data motivates you to learn more about the struggles of immigrants across the country: an excellent starting point is the recent book by SF Chronicle reporter Tyche Hendricks3.

Size, Recent Trends, and Sources

Estimates from the Pew Hispanic Center place the number of unauthorized immigrants to be around 11 million, or less than 4% of the population -- a big number but a rather small fraction of the US population and hardly the enormous problem portrayed by some pundits. (Note the term Foreign-born1 includes legal & unauthorized immigrants, and temporary residents.)

US Foreign-born Population, 2010

How does the US compare with other countries? The US is no outlier when it comes to the proportion of Foreign-born residents. The next chart compares the share of Foreign-born residents in the BRIC countries and a select group of countries from Europe & Asia:

Share of Foreign-born Population, 2005
As far as number of unauthorized immigrants, there was an upward trend in the from 2002-2006, that tapered off sometime during the financial crisis of 2007. In recent years, the number of unauthorized immigrants has declined slightly (down 6.8% from 2007 to 2010):  
Millions of Unauthorized Immigrants in the U.S. (estimates), 2001-2010
As the previous chart suggests, a majority of unauthorized immigrants are from Mexico (close to 63% in Jan/2010). In addition the Top 4 (Central American) countries accounted for 75% based on the most recent data, up from 70% before the 2007 financial crisis:  
Country of Birth of Unauthorized Immigrant Population in U.S.
[ percentage share of Total ]

As of 2010, 1 in 5 resided in California (22%), and 6 states (CA, TX, FL, NY, NY, IL) accounted for close to 60% of all unauthorized immigrants in the US, but only 39% of the nation's population. In the graph below I highlighted a few states that recently passed immigration-related legislation:

Share of Nation's Unauthorized Immigrants (2010)

Labor Market

It's widely held that most immigrants, especially unauthorized migrants, come to the U.S. to work. As the Pew Hispanic Center noted in a recent report, unauthorized immigrants are more likely than the overall population to be of working age. In the graph below I used 2010 Census and DHS figures to compare distributions across age groups. Compared to unauthorized immigrants the overall U.S. population has many more individuals in the "Under 18" and "55 and over" age groups:  
Age of Overall U.S. and Unauthorized Immigrant Populations (2010 Census & DHS)
[ age groups in years ]
The economic contributions of unauthorized immigrants vary widely by state. Since immigration might resurface as an issue in the 2012 Presidential elections, in the chart below I compare two metrics across states important for the popular vote (most populous states) and the electoral college (the battleground states). As noted above, unauthorized immigrants are more likely to be of working age and thus they have a disproportionate share of the labor force (i.e., their percentage share of the labor force is higher than their share of the population). In terms of reliance on labor from unauthorized immigrants the top 6 states are: NV (10%), CA (9.7%), TX (9%), NJ, AZ, GA. In particular Texas has an economy that depends strongly on immigrant workers and it's no surprise that Rick Perry has a more enlightened take on immigration compared to other Republican contenders. For the US, unauthorized immigrants are about 3.7% of the population and 5.2% of the civilian workforce.

(State type refers to the current political classification of each state into Red / Blue / Purple.)  

2010 Share of Unauthorized Immigrants: Population & Civilian Workforce
As you can guess from the previous graph the correlation between state population & the share of unauthorized immigrants in the workforce is weak. A much stronger "predictor" is the demographics within a state: since a majority of unauthorized immigrants are from Central America & Mexico, the correlation between the percentage of Hispanics in the state population & the share of unauthorized immigrants in the workforce is stronger2.  
2010 Share of Unauthorized Immigrants in Workforce vs. 2010 Share of Hispanics2 in Population
The contribution of immigrants to the U.S. economy extends to legal immigrants -- they too have a disproportionate share of the labor force. Below is a similar chart for Foreign-born1 persons, a term that includes both legal and unauthorized immigrants. Ranking states based on their dependence on Foreign-born labor produces slightly different rankings: e.g., NY with 27% of its labor force comprised of Foreign-born residents, is second to CA (35%). But in general states that depend strongly on Foreign-born labor are ones that also rely on unauthorized immigrant labor ( (rank) correlation is 0.86). For the US, Foreign-born residents are about 12.5% of the population and 15.9% of the civilian workforce.  
2009 Share of Foreign-born Population: Population & Civilian Workforce
In Oct/2010 the Immigration Policy Center released a report that assembles detailed statistics on the economic contribution of unauthorized immigrants in the individual states. In particular they provide dollar estimates for contributions towards gross state product and economic activity.  

Live Births & Naturalization

Foreign-born persons have higher birthrates and have a disproportionate share of births. As an example unauthorized immigrants account for less than 4% of the US population but 8% of all child births. Immigration hardliners are especially fond of using high birthrates to lambast undocumented immigrants. As it is, the US, Europe, and Japan have relatively low fertility rates, with the US just hovering above its replacement rate.  
2010 Population & Parents' Status for Births in 2009
[ percentage share of Total ]
The final bit of data is on naturalization (legal immigrants who opt to obtain US Citizenship). There was a 36% increase in naturalizations from 2001-2005 (2.8 million) to 2006-2010 (3.8 million). Compared to the population of the US, adding 6.6 million new citizens (and potential voters) over the past decade, doesn't seem all that much. But in certain small and/or swing states, new voters might turn once automatic seats into competitive races. Rising numbers of Hispanic voters have Democratic party strategists viewing the Mountain West (and to a much lesser extent NC/GA) as moving in their direction.  
Acquisition of US Citizenship by Region/Country of Former Nationality (2001 - 2010)
[ 000's of individuals ]
Related resources:
  • Demographics, Diversity, and the 2010 Census

  • Charts for Decision 2012

  • 2010 U.S. Census Survey: Income by Ethnicity and Gender

  • (1) From MPI: "Foreign born" refers to people residing in the United States who were not US citizens at birth. The foreign-born population includes naturalized citizens, legal permanent residents, certain legal non-immigrants (e.g., refugees and persons on student or work visas), and persons illegally residing in the United States. The civilian labor force includes all civilian persons age 16 and older who were either employed or unemployed in the week prior to participation in ACS.

    (2) Model has slope of 0.19025 & R2 of 0.6. Since Central Americans constitute a majority of unauthorized immigrants, there is an obvious correlation between the share of unauthorized immigrants & the share of Hispanics in the population of the individual states. Absent a precise breakdown of the number of Hispanics within the unauthorized immigrant population of a state, I investigated a similar model where I adjusted the predictor by subtracting the share of unauthorized immigrants from the share of Hispanics in the population of the individual states. The result was very similar: slope of 0.19759 & R2 of 0.48.

    (3) Also see the ACLU's Immigration Myths and Facts .  
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