The Pittsburgh region has lost more residents since 2000 than any U.S. metropolitan area except New Orleans, but there's no hurricane responsible for it dropping 60,309 people.

Instead, the latest population figures from the U.S. Census Bureau show southwestern Pennsylvania with a rare double whammy for a metropolitan area: low international immigration and an imbalance of deaths outpacing births.

The seven-county metropolitan area drew an estimated 15,940 international immigrants between 2000 and 2006, the fewest among the 25 largest cities.

Pittsburgh is among urban areas where the number of people moving to another part of the country exceeds the number moving in. Some regions compensate for that by having more births than deaths, but in the local region it's just the opposite. It had 21,045 more deaths than births between the 2000 census and July 1, 2006. It is the largest metropolitan area where deaths outnumber births.

Pittsburgh remains the nation's 22nd largest metro area, with a population of 2,370,776 in Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland counties.

Christopher Briem, University of Pittsburgh regional economist who analyzes population trends, said the estimates continue a decline resulting from the steel industry's collapse a quarter-century ago, which led to a heavy exodus of working-age people. The proportionally higher elderly population here creates a high death rate, and the economy has not grown enough to attract immigrants to offset the natural population decline.

"People love to think there's a massive flow of new immigrants here, but really, immigrant flow follows job growth and income growth, and we haven't seen any type of turnaround in that to the extent it would create new migration to the region," Mr. Briem said.

On the other hand, he noted, the Census Bureau is only estimating the immigrants seeking permanent settlement in the United States, whether legally or illegally. The estimates do not reflect many foreigners who are here as students or on other temporary visas.

"The important point is we do get international immigrants here, and it is a very highly educated professional flow based on the universities that are here," Mr. Briem said. Unlike other regions, foreign immigrants here are primarily Asian rather than Hispanic.

"We're not getting the blue-collar middle-class immigrant flow here that is the bulk of what's happening in the rest of the country. That's clearly still the case," the economist noted.

Among the nation's 100 largest regions, eight others have lost population since 2000 by lesser amounts than Pittsburgh: Cleveland, Buffalo, N.Y., Youngstown, Ohio, Scranton, Dayton, Ohio, Toledo, Ohio, Rochester, N.Y., and Syracuse, N.Y.

New Orleans' population declined by about 292,000 following Hurricane Katrina.