AUSTIN, Texas — The number of people living in the United States without legal permission fell to 10.7 million in 2016, the lowest number in more than a decade, according to the non-partisan Pew Research Center.

The drop from a peak of 12.2 million in 2007 is almost entirely attributable to a sharp drop in the number of Mexicans entering the country without legal authorization, according to Pew's report released Tuesday.

The last time the number of people in the country illegally was that low was 2004.

Because the numbers are based on 2016 populations, the decline cannot be attributed to President Donald Trump, who took office in January 2017, and his immigration policies.

Most of them are longtime residents

The drop in the population of people illegally living in the country is largely because fewer new immigrants are coming to the country, which means more are longtime United States residents.

About two-thirds have lived in the United States for more than a decade and a greater share, 43 percent in 2017 versus 32 percent in 2007, have U.S.-born children.

About half of the people living in the country illegally are from Mexico — about 1.5 million fewer than in 2007, according to Pew.

However, about 375,000 more people from El Salvador, Guatemala and Honduras came to the U.S. without legal permission between 2007 and 2016, for a total of about 1.85 million in the country. Central America is the only region from which more immigrants arrived in the years from 2007 to 2016, according to Pew.

The total number of people who came to the U.S. illegally and were originally from South America, Europe and Canada dropped while those from the Caribbean, Asia, the Middle East and Africa remained steady.

The report of fewer people living in the country illegally comes after the administration shut down the San Ysidro port of entry in California for hours Sunday after border officers used tear gas on men, women and children to keep them from entering the U.S. illegally and asking for asylum.

It is a misdemeanor to cross the border without legal permission. But once across the border, the law allows a person to request asylum.

The number of adult unauthorized immigrants in the workforce, 7.8 million, was lower in 2016 than a decade earlier and they made up less than 5 percent of the workforce, also a drop from 2007 when they were about 5.4 percent.

The number of unauthorized immigrant workers in low-skilled jobs declined, while those in management, business and professional jobs rose by a third, Pew said.

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