A new study from the Pew Hispanic Center found that the number of illegal immigrants in the United States dropped significantly for the first time in two decades -- but the population out of Mexico has held steady since reaching its peak in 2007.
Though the study could show up as ammunition in the debate over anti-illegal immigration laws in Arizona and elsewhere, the data does not show that unauthorized residents are fleeing back to Mexico. Fewer illegal immigrants from Mexico are coming to the United States, but those here are generally staying put -- apparently unfazed by the economic downturn, hostile climate and federal enforcement.
The data shows "no evidence of a recent increase in the number of Mexican-born migrants returning home from the U.S.," the study said.
The bulk of the dropoff comes from those immigrants out of other Latin American countries, in South America, Central America and the Caribbean.
Among illegal immigrants from Latin American countries other than Mexico, the population declined 22 percent between 2007 and 2009. The total number of illegal immigrants fell 8 percent during that time, from 12 million to 11.1 million.
But the population from Mexico, where drug cartel-fueled violence has prompted concern along the U.S. border, grew rapidly since 2000 and has not receded much. The population, according to the Pew Hispanic Center, went from 4.6 million in 2000 to 7 million in 2007 -- the number dipped to 6.7 million in 2009. The percentage of illegal immigrants from Mexico has grown from 51 percent in 2001 to 60 percent last year, according to Pew.
As with other populations, there has been a sharp dropoff in the number of illegal immigrants from Mexico crossing the U.S. border. The annual traffic went from a half-million earlier in the decade to 150,000 between 2007 and 2009.
Overall, illegal immigrant traffic fell from 850,000 annually in the first half of the decade to 300,000 over the past two years. The easing of traffic has been attributed to economic circumstances as well as enforcement.
Rep. Steve King, R-Iowa, said the economic factors are probably more significant.
"I believe that it's the economic circumstances more than the enforcement," he said. "We do not have a culture to get operational control of the border."
The federal government announced last month that it deported a record 380,000 illegal immigrants in the last fiscal year.
But King noted that Immigration and Customs Enforcement recently instituted a new policy to halt deportation proceedings for some illegal immigrants married or related to a legal resident who has filed a petition to stay.
The Obama administration is trying to sustain enforcement efforts. The administration has started deploying a force of 1,200 National Guard troops to the southwest border and has approved a $600 million bill to fund 1,500 new Border Patrol, ICE and DEA agents.