The Homeland Security Department estimates the number of illegal immigrants living in the U.S. fell about 7 percent to 10.8 million in January 2009.
The drop is the second in two years. The population rose to 11.8 million in January 2007. It fell to 11.6 million in January 2008.
The government says about two-thirds of the illegal immigrants who were in the country in 2009 entered the U.S. before the year 2000. About the same share were from Mexico.
The Homeland Security Department noted that the decline has coincided with the economic downturn in the U.S.