New U.S. Census Bureau figures show that immigration tapered off nationally last year. But the San Joaquin Valley continues to grow more Hispanic, with almost two-thirds of children younger than 10 falling into that ethnic group.
The nation added about a half million immigrants in 2007, down from more than 1.8 million the year before, according to the new American Community Survey estimates.
That gave the country an estimated total of more than 38 million immigrants -- of whom slightly more than 10 million were in California, up 122,000 from 2006. Like the nation, California's rate of increase also slowed last year from the prior year, although it appeared to drop less than the national rate.
Several San Joaquin Valley counties showed gains as well, although the survey's small sample size made it impossible to say whether the increases were real. In any case, Hispanics now make up the largest racial or ethnic group in each central San Joaquin Valley county. In some, they have become the outright majority. In the others, they soon will be the majority as the population ages.
In Merced County, 39 percent of families speak Spanish primarily in their homes. And 17 percent of all residents are not U.S. citizens. The median age in the county is a sprightly 29 years old, compared to 37 for the United States as a whole.
In Fresno County, Hispanics now make up about 48 percent of the population, but an estimated 53 percent of people in their 20s, 56 percent of teens, and 60 percent of children under 10. The under-10 proportion is even higher in most counties -- as high as 73 percent in Tulare County, for example.
Immigration may account for part of this demographic shift. But experts say an even bigger factor may be that Hispanic women in the five counties are giving birth at a rate almost one-third higher than non-Hispanic whites.
"Some people make the assumption that this increased Latino population is because of immigration, but most of it is not," said David Hosley, president of the Great Valley Center, a Modesto-based nonprofit group focused on issues relating to the Valley's future.
The new data come from the bureau's American Community Survey, an annual questionnaire that is intended to replace the traditional "long form" version of the regular census. The survey provides detailed economic and social data for areas with 65,000 or more people.
At more than 38 million, the number of immigrants in the U.S. is now at an all-time high. Immigrants made up 12.6 percent of the population in 2007, the largest share since 1920, when the U.S. was nearing the end of its last immigration boom, one that brought millions of people from Europe to the United States.
Fourteen states showed declines in the estimated number of immigrants from 2006 to 2007, including New Jersey, New Mexico, Vermont and South Dakota.
"Immigrants have always come to the United States for jobs, but before they went to big immigration magnets to be with family or other immigrants," said William Frey, a demographer at the Brookings Institution who analyzed the numbers. "Now the geography of where these people move is much more tied to the economy than ever before."
For the central San Joaquin Valley, the numbers amplify a trend that has been building for the past couple of decades. The existing population, whiter and older, is gradually being replaced by younger generations that are mostly Hispanic.
It's a demographic change that creates challenges for schools, which must teach children who may hear only Spanish at home, and for a labor force that must prepare to absorb a generation that dwarfs the postwar baby boom.
But consider the alternatives, says Hans Johnson, senior fellow at the Public Policy Institute of California.
"Many people regard the presence of immigrants and their children as a very positive force," Johnson said. "In general, you'd rather be in a place like Fresno, where you have to deal with growth, than a place like Iowa where the population is declining, towns are dying, and businesses are being boarded up."