WASHINGTON — 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.