Pittsburgh and Philadelphia, the state's two largest cities, continue to lose residents, new U.S. Census Bureau figures show.

Pittsburgh's population slipped to 322,450 as of July 1, 2004, down from 325,599 a year earlier, a decline of just over 3,000, or 1 percent, dropping it to 56 among the nation's largest cities.

That put Pittsburgh behind Raleigh, N.C., which surpassed the city by adding an estimated 10,460 residents, pushing its population to 326,653.

Philadelphia remained the nation's fifth-largest city, behind Houston but ahead of fast-gaining Phoenix, even though its population slipped nearly 7,000, or half a percent, to 1,470,151.

Both Pittsburgh and Philadelphia have been losing population for decades, initially reflecting a shift to the suburbs and later a move by residents to fast-growing locales in the West and Sunbelt, which continue to lure residents from all over the country.

Twenty-two of the nation's 25 fastest-growing cities with populations of 100,000 or more in 2004 were in Florida, California, Nevada, Arizona or Texas, led by Port St. Lucie, Fla., which led the nation with a 12 percent increase, from 105,707 to 118,396 in the 12 months ended last July.