WASHINGTON (AP) — New census data released Thursday affirm a clear and sustained drop in illegal immigration, ending more than a decade of increases.

The number of illegal immigrants in the U.S. dropped to an estimated 11.1 million last year from a peak of 12 million in 2007, part of an overall waning of Hispanic immigration. For the first time since 1910, Hispanic immigration last year was topped by immigrants from Asia.

Demographers say illegal Hispanic immigration — 80 percent of all illegal immigration comes from Mexico and Latin America — isn’t likely to approach its mid-2000 peak again, due in part to a weakened U.S. economy and stronger enforcement but also a graying of the Mexican population.

The finding suggests an uphill battle for the Republicans, who passed legislation in the House last week that would extend citizenship to a limited pool of foreign students with advanced degrees but who are sharply divided on whether to pursue broader immigration measures.

In all, the biggest surge of immigration in modern U.S. history ultimately may be recorded as occurring in the mid-1990s to early 2000s, yielding illegal residents who now have been settled in the U.S. for 10 years or more. They include migrants who arrived here as teens and are increasingly at risk of “aging out” of congressional proposals such as the DREAM Act that offer a pathway to citizenship for younger adults.

The numbers are largely based on the Census Bureau’s Current Population Survey through March 2011. Because the Census Bureau does not ask people about their immigration status, Passel derived estimates on illegal immigrants largely by subtracting the estimated legal immigrant population from the total foreign-born population. The numbers are also supplemented with material from William H. Frey of the Brookings Institution and Mark Mather of the Population Reference Bureau, who reviewed data released Thursday from the Census’ American Community Survey.

The data showed that 11.1 million, or 28 percent, of the foreign-born population in the U.S. consists of illegal immigrants, virtually unchanged since 2009 and roughly equal to the level of 2005. An additional 12.2 million foreign-born people, 31 percent, are legal permanent residents with green cards. And 15.1 million, or 37 percent, are naturalized U.S. citizens.

Fewer Mexican workers are entering the U.S., while many of those immigrants already here are opting to return to their homeland, resulting in zero net migration from Mexico.

In 2007, legal and illegal immigrants made up equally large shares of the foreign-born population, at 31 percent, due to ballooning numbers of new unauthorized migrants seeking U.S. construction and related jobs during the mid-2000s housing boom. Naturalized U.S. citizens then represented 35 percent.

Broken down by geography and race, roughly half of all states last year posted declines or no change in their numbers of foreign-born Hispanics, including big immigrant states such as California and New York as well as economically hard hit areas in Arizona, Georgia and North Carolina, which previously had seen gains.

Foreign-born Asians were a bigger source of population gain than Hispanic immigrants in California, New York, Virginia, Illinois and New Jersey. Newly moving into suburban communities, the Asian population spread out more across the southeastern U.S. and Texas, increasing their share in 93 percent of the nation’s metropolitan areas.

As a whole, foreign-born residents are slowly graying, with 44 percent now age 45 or older. They are more likely than in 2007 to be enrolled in college or graduate school (39 percent, up from 32 percent) and to be single (17 percent married, down from 22 percent).

Births to immigrant mothers also are on the decline, driving the overall U.S. birth rate last year to the lowest in records dating back to 1920.

Posted 12/6/2012