WASHINGTON (AP) - The number of illegal immigrants in the U.S. has dropped for the first time in 20 years as substantially fewer undocumented workers from Mexico, Latin America and elsewhere are crossing the border in search of jobs, an independent research group says.
The analysis by the Pew Hispanic Center suggests the nation's economic downturn and increased border enforcement have reduced the number of illegal immigrants, who make up roughly 4 percent of the U.S. population.
The findings come amid bitter debate over Arizona's strict new immigration law - now being challenged in federal court after lawmakers passed it earlier this year. The Obama administration contends the state law usurps federal authority and promotes racial profiling, while Arizona says states are justified to step in if federal enforcement falls substantially short.
The study released Wednesday estimates that 11.1 million illegal immigrants lived in the U.S. in 2009. That represents a decrease of roughly 1 million, or 8 percent, from a peak of 12 million in 2007, before Arizona intervened with its new enforcement measures.
The study, based on an analysis of 2009 census data, puts the number of illegal immigrants about where it was in 2005.
The 11.1 million is slightly higher than the Homeland Security Department's own estimate of 10.8 million. The government uses a different census survey that makes some year-to-year comparisons difficult.
Much of the recent decrease comes from a sharp drop-off in illegal immigrants attempting to cross the border into the U.S., particularly those from the Caribbean, Central America and South America. An increase in unauthorized immigrants leaving the U.S., by deportation or for economic reasons, also may have played a factor.
States in the Southeast and Southwest saw some of the biggest declines in the number of illegal immigrants from 2008 to 2009, including Florida, Nevada and Virginia. Arizona saw a decrease, but it was too small to be statistically significant.
It's hard to figure out how much of the decline to attribute to the bad economy and how much to immigration enforcement, said Jeffrey Passel, a senior demographer at Pew who co-wrote the analysis.
"They're certainly acting together," he said. Passel said illegal immigrants now find it more expensive and dangerous to cross into the U.S. and also have less incentive to do given the languishing job market in construction and other low-wage industries.
"While people are arguing the government is not stopping illegal immigration, our data suggests the flow of undocumented immigrants sneaking into the country has dropped dramatically," Passel said.
He declined to predict how long the decline in illegal immigration may last, other than to say it could take a while before unemployment in the U.S. substantially improves.
The estimates by Pew will add to the political back-and-forth on immigration reform.
Boosted by immigration and high fertility among Latinos, minorities now make up roughly half the children born in the U.S., part of a historic trend in which they are projected to become the new U.S. majority by mid-century. Roughly one in four counties currently have more minority children than white children or are nearing that point.
Still, the Census Bureau has made clear that projected minority growth - particularly among Hispanics - could change substantially depending on immigration policies and the economy. President Barack Obama, who is challenging the Arizona law, has pledged to push an overhaul of federal immigration law but has declined to set a timeline.
Following the passage of Arizona's immigration law - which is now largely on hold as it's reviewed by the courts - more than a dozen states were considering similar legislation or issued legal opinions aimed at strengthening immigration enforcement. They include Florida, Virginia, South Carolina and Utah.
Other Pew findings:
- The states with the highest percentage of illegal immigrants were California (6.9 percent), Nevada (6.8 percent), Texas (6.5 percent) and Arizona (5.8 percent). The numbers are expected to play an important factor in whether those states lose or gain fewer U.S. House seats than expected after the 2010 census.
-Illegal immigrants make up about 28 percent of the foreign-born population in the U.S., down from 31 percent in 2007.
-The unemployment rate for illegal immigrants in March 2009 was 10.4 percent - higher than that of U.S.-born workers or legal immigrants, who had unemployment of 9.2 percent and 9.1 percent, respectively.
The Pew analysis is based on census data through March 2009. Because the Census Bureau does not ask people about their immigration status, the estimate on illegal immigrants is derived largely by subtracting the estimated legal immigrant population from the total foreign-born population. It is a method that has been used by the government and Pew for many years and is generally accepted.