BOSTON (AP) – Massachusetts, Rhode Island and New York were the only states to lose population from 2004 to 2005, according to estimates released Thursday by the U.S. Census Bureau.

Massachusetts lost more than 8,000 residents between July 2004 and July 2005, a decrease of 0.1 percent, making it the only state to lose population in each of the past two years. Rhode Island lost more than 3,000 residents, down 0.3 percent, the Census Bureau estimated.

Experts attribute the trend to soaring housing costs, a stagnant job market and the arrival of fewer immigrants.

“There are reasons for concern here,” said Marc Draisen, executive director of the Metropolitan Area Planning Council. “Housing costs are a dramatic driver when it comes to people making decisions to move to other states.” Most of the states with the largest population growth are in the South and West. Nevada, with an estimated population increase of 3.5 percent, was the fastest growing state for the 19th consecutive year, followed by Arizona, Idaho, Florida and Utah.

The nation’s population increased by 2.8 million, or 0.9 percent, to 296.4 million, according to the Census Bureau.

Last year, Massachusetts was the only state with an estimated population decrease. This year, it is joined by Rhode Island, New York and the District of Columbia.

“It’s an aging population in Rhode Island,” said Mark Brown, principal planner for the Rhode Island’s Office of Statewide Planning. “We’re maintaining the middle-aged population, but we’re losing some of our elderly to warmer climates, and some of our post-college younger people are looking for greener pastures.”

States with declining populations are in danger of losing House seats when congressional districts are redrawn in 2010. They also could see a severe “brain drain,” losing highly educated workers to other states, said Michael Goodman, director of economic and public policy research for the Donahue Institute at the University of Massachusetts.

“The lack of labor would be a serious threat to future growth,” Goodman said.

AP-ES-12-22-05 1541EST