The average annual inflow of unauthorized immigrants to the United States was nearly two-thirds smaller in the March 2007 to March 2009 period than it had been from March 2000 to March 2005.
The flow of immigrants from Mexico to the United States has declined sharply since mid-decade, but there is no evidence of an increase during this period in the number of Mexican-born migrants returning home from the U.S.
There were 11.9 million unauthorized immigrants living in the United States in March 2008. The size of the unauthorized population appears to have declined since 2007.