The number of unauthorized immigrants living in the United States was lower in 2016 than at any time since 2004. This decline is due mainly to a large drop in the number of new unauthorized immigrants, especially Mexicans, coming into the country. The origin countries of unauthorized immigrants also shifted during that time, with the number from Mexico declining and the number rising from only one other region, Central America, according to the latest Pew Research Center estimates.

Here are five facts about the unauthorized immigrant population in the U.S.

U.S. unauthorized immigrant total rises, then falls1There were 10.7 million unauthorized immigrants in the U.S. in 2016, representing 3.3% of the total U.S. population that year. The 2016 unauthorized immigrant total is a 13% decline from the peak of 12.2 million in 2007, when this group was 4% of the U.S. population.

2The number of Mexican unauthorized immigrants declined since 2007, but the total from other nations changed little. Mexicans made up half of all unauthorized immigrants in 2016, according to the Center’s estimate, compared with 57% in 2007. Their numbers (and share of the total) have been declining in recent years: There were 5.4 million Mexican unauthorized immigrants living in the U.S. in 2016, down from 6.9 million in 2007.

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Meanwhile, the total from other nations, 5.2 million in 2016, remained about the same as in 2007, when it was 5.3 million. The number of unauthorized immigrants has grown since 2007 only from one birth region: Central America, from 1.5 million that year to nearly 1.9 million in 2016. This growth was fueled mainly by immigrants from the Northern Triangle nations of El Salvador, Guatemala and Honduras.

The totals also went down over the 2007-2016 period from South America and the combined region of Europe plus Canada. The remaining regions (the Caribbean, Asia, Middle East-North Africa, sub-Saharan Africa and the rest of the world) did not change significantly in that time.

3The U.S. civilian workforce includes 7.8 million unauthorized immigrants, representing a decline since 2007. Between 2007 and 2016, the number of unauthorized immigrant workers fell, as did their share of the total U.S. workforce over the same period. This group accounted for 4.8% of those in the U.S. who were working or were unemployed and looking for work. The number of unauthorized immigrant men in the prime working ages of 18 to 44 also declined, but not women.

Compared with their 4.8% share of the civilian workforce overall in 2016, unauthorized immigrants are overrepresented as a share of the workforce in farming occupations (24%) and construction occupations (15%). In all industries and occupations, though, they are outnumbered by U.S.-born workers.

4Six states account for 58% of unauthorized immigrants: California, Texas, Florida, New York, New Jersey and Illinois. But individual states have experienced different trends. From 2007 to 2016, the unauthorized immigrant population decreased in a dozen states: Alabama, Arizona, Arkansas, California, Florida, Illinois, Michigan, Nevada, New Jersey, New Mexico, New York and Oregon. In three states, the unauthorized immigrant population rose over the same period: Louisiana, Maryland and Massachusetts.

5A rising share of unauthorized immigrants have lived in the U.S. for more than a decade. About two-thirds (66%) of unauthorized immigrant adults in 2016 had been in the U.S. more than 10 years, compared with 41% in 2007. A declining share of unauthorized immigrants have lived in the U.S. for less than five years – 18% of adults in 2016, compared with 30% in 2007. In 2016, unauthorized immigrant adults had lived in the U.S. for a median of 14.8 years, meaning that half had been in the country at least that long.

To learn more: Explore unauthorized immigrant population trends for states, birth countries and regions.

Note: This post was originally published on Nov. 18, 2014, and has been updated.