Study: Number of New Illegal Immigrants Has Fallen Sharply

The number of illegal immigrants entering the United States each year has dropped substantially since the first half of this decade, according to a study released today by the Pew Hispanic Center. A sluggish economy and stepped up enforcement of immigration laws could be behind the decline.

The study found that the number of illegal immigrants entering the United States each year has dropped from an average of 800,000 per year between 2000 and 2004 to 500,000 per year between 2005 and 2008.

By contrast, the inflow of immigrants who are legal permanent residents has remained relatively steady at about 650,000 per year, exceeding the number of illegal immigrant arrivals for the first time in a decade.

Despite the slowing growth rate of the illegal immigrant population, the study's authors estimated that its size has increased by 40 percent over the past decade, from an estimated 8.4 million in 2000 to an 11.9 million in March. Illegal immigrants now make up about 4 percent of the U.S. population and about 30 percent of the nation's foreign-born population. About four out of five illegal immigrants come from Latin American countries, mainly Mexico, and more than four out of 10, or 5.3 million, arrived since the start of the decade.

The U.S. Census Bureau does not ask people their immigration status. So the authors of the Pew report estimated the number of illegal immigrants by finding the difference between the number of foreigners who can be accounted for through such records as visas, permanent residency permits and naturalizations and the total number tallied by the census.

The study's authors cautioned that their estimates could not explain the drop in the number of illegal immigrants entering the country. However, they pointed to a number of possible causes. For instance, a slowdown in U.S. economic growth has had a disproportionate impact on foreign-born Latinos workers at the same time that economic growth in Mexico and other Latin American nations has been stable. The heightened focus on enforcement of immigration law has also generated concern among many Hispanics, according to another recent study by the Pew Hispanic Center, a nonpartisan research organization based in Washington.