The city of Pittsburgh continued its population decline between 2004 and 2005, losing more than 4,000 people while remaining the nation's 57th-largest city, according to U.S. Census Bureau estimates released yesterday.

The estimated population of 316,718 on July 1, 2005, places the central city right behind Tampa, Fla., and ahead of Cincinnati. Pittsburgh proper lost 1.3 percent of its population, making its net change 245th out of 254 cities with 100,000 or more people. Among cities with a worse decline were Cleveland, New Orleans, Detroit, Boston, Cincinnati, St. Louis and Norfolk, Va.

Pittsburgh's seven-county region of 2,401,575 ranked 21st in the nation in the last metropolitan area ranking, done in 2004. The populations of both the city and region have gradually declined because of a combination of factors, including a relatively high percentage of elderly residents who contribute to more deaths than births taking place.

The area also has low international immigration for an urban center, and creates too few jobs to attract as much domestic in-migration as many cities.

The list of the 10 fastest-growing cities from 2004 to 2005 included four from California (Elk Grove, Moreno Valley, Rancho Cucamonga and Irvine); three from Florida (Port St. Lucie, Cape Coral and Miramar); two from Arizona (Gilbert, Chandler); and North Las Vegas, Nev.