Illegal immigration is falling in America. Experts say that's because of the struggling economy and stepped-up enforcement.

The Pew Hispanic Center reports the number of illegal immigrants entering the United States has slowed significantly in recent years, and is now below the number of people coming into the country legally. The Washington think tank estimates there were 11.9 million illegal immigrants in the country this past spring. That's down a-half million from a year ago.

The study does not deal with the reasons for the decrease. But other researchers cite the economy and enforcement of immigration laws. One expert says word quickly gets back to Mexico and Latin America about the decline in construction, service and other low-skill jobs in the United States.