PHOENIX " The illegal-immigrant population has fallen an estimated 11 percent nationwide over the past year and perhaps even more in Arizona, according to a report by a Washington organization that promotes less immigration.
The Center for Immigration Studies said the drop of about 1 million illegal residents happened from August to May even as the number of legal immigrants increased.
The number of illegal immigrants may have fallen as much as 18 percent in Arizona since August although the data is too spotty to say with confidence, said Steven Camarota, director of research for the center.
Estimates before the center's study put the number of illegal immigrants at 12 million nationwide and 500,000 in Arizona.
The Immigration Policy Center, an organization frequently at odds with Caramota's, agreed that the number of illegal immigrants may have fallen but believes the economy is by far the biggest factor.
Jeanine L'Ecuyer, a spokeswoman for Gov. Janet Napolitano, said a drop in illegal immigrants would be consistent with federal reports of a decline in apprehensions and the U.S. Border Patrol's stepped-up efforts since 2006 seem to have helped.