WASHINGTON AND LOS ANGELES — More than three decades of rapid growth in the country's foreign-born population came to a halt last year, census data show, as surging unemployment made the U.S. economy less attractive to outsiders.
In California, which has a long history of attracting immigrants, the number of foreign-born residents actually declined, shrinking 1.6%.
"This is clearly a consequence of the economy, with the biggest impact on Mexican and low-skilled immigrants," said William Frey, a demographer at the Brookings Institution who analyzed the census figures, which are to be officially released today. "It shows that these immigrants respond to the economy."
Nationwide, the number of foreign-born residents fell an estimated 99,000, or 0.3%, to 37.97 million.
The data come from the Census Bureau's annual survey of about 3 million Americans, not the entire population. The survey's margin of sampling error is high enough to make it possible that the number of foreign-born people in the country actually remained unchanged from 2007 to 2008 rather than declined.
Nonetheless, the figures suggest a dramatic break from a long wave of increasing migration to the U.S., particularly from Asia and Latin America, that followed a major change in immigration policy in 1965.
In the two decades that preceded 2008, the country's foreign-born population grew an average of almost 1 million a year, including by nearly 512,000 in 2007.
In California, the number of foreign-born people dropped 165,000 last year to 9.9 million. The reversal in the state was driven by several Southern California counties with sharp declines, such as Los Angeles, with a slide of 3%, San Bernardino, down 3.6%, and Ventura, down 4.1%. Orange and Riverside counties showed smaller decreases.
But the slowing of the increase in California's foreign-born population began well before the latest recession, said Dowell Myers, a professor and urban demographer at USC.
In the 1980s, for example, many immigrants targeted California because of their family and cultural ties to the state's already established immigrant communities. But during the aerospace-led downturn of the early 1990s, immigrants began moving more throughout the country, where they found employment more plentiful and housing more affordable.
"Now, they have contacts across America who say, 'Hey, I can get you a job and a house for one-third the price,' " Myers said.
The trend of immigrants' following the availability of jobs, even if it means settling in areas relatively new to foreigners, has continued into this decade.
"The economic drivers for where immigrants decide to settle have increased in importance," said Sarah Bohn, a research fellow at the Public Policy Institute of California.
As a result, California's working-age immigrant population grew an average of only 2% a year in this decade through 2007, down from 4.4% in the 1990s and 9.5% in the '80s.
The new census data, which come from the bureau's American Community Survey, an annual poll begun this decade, show the biggest drops last year in foreign-born residents were in California, Arizona and Florida -- three of the states hit hardest by the recession. Texas, whose economy has outperformed most other states, saw the biggest gain, followed by Georgia and New York.
Some groups supporting greater limits on immigration seized on the new figures, saying they threw cold water on the argument that illegal immigrants should be given amnesty because they are here to stay, and that little can be done to change that.
"Many of us always thought illegal immigrants were anchored in the U.S.," said Steve Camarota, director of research at the Center for Immigration Studies, a Washington think tank that seeks fewer immigrants. "This new data suggest that's not the case."
The statistics "imply very strongly that fewer people are coming and significantly more are going home," he added.
Other researchers disputed that notion, saying there is no evidence that an increased number of foreign-born residents from Mexico, who constitute most illegal immigrants, are returning there.
"What appears is that the number of new immigrants has declined substantially, especially undocumented immigrants," said D'Vera Cohn, a senior writer at the Pew Research Center.
She and demographer Jeffrey Passel reported in a recent study that data from the Mexican government show no rise in the number of arrivals home from 2006 through early 2009.
Other highlights from the Census Bureau survey:
* More workers turned to mass transit and carpooling last year as gas prices soared. The number of workers driving to work by themselves slid to 75.5% in 2008, the lowest level in a decade, from 76.1% in 2007. The percentage of carpoolers increased to 10.7% from 10.4%.
* The percentage of women ages 15 and older in the population who had never married rose to 28.1% last year, up from 27.6% in 2007 and 27.3% in 2006.
* The inflation-adjusted median household income fell in five states -- California, Florida, Indiana, Arizona and Michigan -- in 2008 from 2007. Just one state had a decline the year before. The median household income in California last year was $61,021.
Five states -- Kansas, Louisiana, New Jersey, New York and Texas -- posted a gain in household income last year, down from 33 states in 2007.
* The American Community Survey has shown wide fluctuations from year to year in the increase in the country's foreign-born population. The smallest gain was 374,391 in 2001. The largest was 1.86 million in 2006.
Times staff writer Doug Smith and Times data analyst Sandra Poindexter contributed to this report.