SACRAMENTO (AP) - Gov. Arnold Schwarzenegger is fond of referring to California as a nation state.
Population figures released Wednesday show that if the Golden State was its own country, it would be right there with Poland.
California's population is nearing 38 million, up 11.5 percent since the 2000 census, according to estimates by the state Department of Finance.
Among nations, 33 countries have more people, with Poland's population running just ahead at 38.5 million. The latest figure still means California has more people than Canada.
The department calculated that the nation's most populous state had about 37,771,000 people as of July 1. It added 438,000 more residents in the previous year.
Just more than 12 percent of the 301 million people in the U.S. live in California.
Los Angeles County alone is home to nearly 10.3 million people, a population slightly higher than Michigan's. By contrast, mountainous Alpine County had just 1,261 residents, the fewest in California, the department said in its annual population report.
California now has about 14 million more residents than the next largest state, Texas, which has 23.5 million.
Riverside County was California's fastest growing in both number of new residents and percentage increase, while rural Sierra County lost nearly 2 percent of its population.
The state grew by 3.9 million people since the last census. But the annual growth rate of 1.2 percent is slower than the 2 percent growth in 2000.
There were 565,000 births and 238,000 deaths between June 2006 and July 2007, for a net increase of 327,000 residents. That accounted for three-quarters of the state's growth.
"That's a train that's not likely to slow down," said Mary Heim, chief of the department's demographic research unit.
More volatile is the number of people moving into or out of California from other states or nations, shifts driven largely by economic conditions and the state's high cost of living.
The last three years, California has seen more people move to other states than moved into the state from elsewhere in the U.S., including a net loss to other states of 89,000 last year.
"But that's being more than counterbalanced by immigration from abroad," Heim said.
With about 200,000 more legal and illegal immigrants, California saw a net increase of 111,000 people from other states and nations.
Riverside, Imperial and Sutter counties each saw their populations grow by more than 3 percent during the year. Just two of the state's 58 counties lost population, neighboring Plumas and Sierra counties in the northern Sierra Nevada.
Five counties accounted for nearly half the state's population growth, four of them in Southern California: Riverside, Los Angeles, San Diego, Santa Clara and San Bernardino.
California's population remains concentrated mostly along its coast, the figures show.
Nine counties have more than 1 million residents and account for 70 percent of the state's population: Los Angeles, San Diego, Orange, Riverside, San Bernardino, Santa Clara, Alameda, Sacramento and Contra Costa.
But the big population growth is inland: Riverside and San Bernardino counties east of Los Angeles; and Sutter and Madera counties in Northern California. That is likely driven by employment growth in the Los Angeles, Sacramento and Fresno areas, Heim said.
"These are counties that are becoming more suburban," she said.
Riverside County spokesman Ray Smith wasn't surprised by the finding. He cited a report that 37,000 new jobs would be created in Riverside and neighboring San Bernardino counties in 2007.
"We've got historically inexpensive housing here in Riverside County. It costs more than it did, but it's still more affordable than other areas of Southern California," Smith said.
"It does create challenges," Smith said of the rapid growth.
Among other responses, the county has a 10-year, $2 billion plan to widen four major highways, as well as programs to protect open space and wildlife habitat.
Ironically, the big concern now is empty houses, said Hans Johnson, a demographer with the Public Policy Institute of California in San Francisco.
"With the foreclosure crisis we're having and the downturn in housing, I think what we're going to be talking about is the decrease in growth," Johnson said. "Building permits are way, way down. Certainly the amount they're generating is way, way down from where it was a few years ago."
That's a particular problem in counties such as Riverside, which grew to depend on building fees to fund services, Johnson said.
Riverside, for instance, is seeing a decline in money from a "transportation mitigation fee" on new housing that now isn't being built.
He noted the state is devoting billions in voter-approved bonds to improving its transportation network.
"More growth will require more and more investment in that area," Johnson said.
The population decline is the bigger concern in counties such as Sierra, which has seen its population fall from 3,629 in 2000 to 3,400 as of last July.
"You have fewer people in these smaller communities to keep everything functioning - the volunteer fire department, the schools," county Assessor Donald G. Iversen said.
The state Department of Finance calculates the population based on birth and death statistics, address changes recorded by the California Department of Motor Vehicles and the U.S. Internal Revenue Service, as well as housing and school statistics.
Since the 2000 census, California had 3.9 million births and 1.7 million deaths, for a net increase of 2.2 million. Since then, the state also has added 1.5 million foreign immigrants and 125,000 people from other states to reach its current population, the department said.
The state has added nearly 8 million people since 1990.