WASHINGTON - Battered by the recession, more older Americans are staying put in traditional big cities to hold on to jobs, creating slowdowns in population growth at once-popular retirement destinations widely found in the South and West.

Census estimates this year capture the effect of the housing downturn and economic recession, including the critical period after the financial meltdown in late 2008, on the nation's counties and metropolitan areas.

The population figures show that annual growth of retirement-destination counties slipped from 3.1 percent between 2000 and 2007, to 1.7 percent between 2007 and 2009, despite the large cohort of baby boomers who are reaching retirement age.

In all, 126 of the 440 retirement counties - those that attract large numbers of people 60 and older - lost population during the recession, many of them in Sun Belt areas such as Florida, Arizona, New Mexico, and California. In Florida, 33 of its 43 retirement counties grew more slowly, while seven others, led by Daytona Beach in Volusia County, lost population.

Retirement magnets in other parts of the nation saw significant declines, too, including Pennsylvania, Ohio, and Michigan.

"Baby boomers helped fuel housing and population growth in retirement areas earlier in the decade, and now they are playing an important role in the decline," said Mark Mather, associate vice president of the Population Reference Bureau, who analyzed the retirement figures.

In the next few years, the number of older workers will increase 11.9 million, making up nearly 1 in 4 workers by 2016 as more seniors hold on to jobs due partly to shriveled home values and decreased stock portfolios.

"A growing number of baby boomers want to continue working after age 65, and many are choosing to live closer to cities to keep their options open," Mather said.

The numbers, current as of July 2009, are the last population estimates for metros and counties before the official 2010 head count is completed later this year. Data from the 2010 census, now under way, will be used to redraw legislative boundaries and distribute more than $400 billion in federal aid.

Overall, fewer people are migrating to wider spaces in the Sun Belt in a reversal from earlier in the decade. Once booming in population because of the housing bubble, many of these areas are now experiencing sharply slower growth.

For the first time in decades, more people moved out of Las Vegas than moved in, due to foreclosures and a depressed tourism industry, while Orlando, Fla., had more people move out for a second year in a row. Also seeing decreases in residents moving in were Phoenix, Atlanta, and Raleigh, N.C.

In contrast, Philadelphia and Cleveland stanched some population losses, while New York, Los Angeles, Boston, and Chicago reported gains. Boosted by a burst of federal hiring, the Washington region had more residents move in than move out for the first time in seven years.

"The migration slowdown has not let up," said William H. Frey, a demographer at Brookings Institution who analyzed the data. "The decade that began with 9/11, a dot-com bust, then a housing boom and bust, and more recently the Great Recession, has turned traditional Snow Belt to Sun Belt migration on its head.

"It remains to be seen when and where a turnaround in the nation's unforeseen migration patterns will take place," he said.

One exception was Texas, a Sun Belt state where substantial gains due to a stronger labor market and immigrant growth occurred. For the second year in a row, Dallas-Fort Worth and Houston ranked first and second among metros with the most numerical gains, each adding more than 140,000 people.

Texas, which also had Austin and San Antonio in the top-20 list, stands to gain up to four House seats after the 2010 census.

Since the 2000 census, 21 cities have moved up in the rankings of the 50 most-populated U.S. metro areas. They included Dallas, which moved to the fourth spot behind New York, Los Angeles, and Chicago. Eighteen cities moved down, among them Philadelphia, which slipped from fourth to fifth.

Results from the official 2010 head count will be published beginning in December.

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