The slowing pace of population growth in northeastern states is a decades-long trend spurred, in part, by the region's loss of manufacturing jobs, said Janice Madden, a University of Pennsylvania sociology professor who follows population shifts. Payrolls at Pennsylvania manufacturers declined 35% over the past 10 years, according to U.S. Department of Labor data.

Losing Political Clout

Pennsylvania's tepid population growth means the loss of another U.S. House of Representatives seat, the eighth-straight time the state's congressional delegation has been reduced by a census count, said Terry Madonna, director of the Center for Politics and Public Affairs at Franklin & Marshall College in Lancaster, Pennsylvania.

"Pennsylvania, which once had 30 House seats, will be down to 18" when Republicans finish the state redistricting process, Madonna said in an interview. Republicans control both houses of the state General Assembly and the governor's seat.

Mark Critz, a House Democrat who represents Pennsylvania's 12th Congressional District, is likely to have his seat redistricted out of existence, Madonna said. Critz won a special election in May after Representative Jack Murtha died. Critz worked as a long-time aide to Murtha, an 18-term Democrat from western Pennsylvania who served as head of a House defense appropriations subcommittee.

Anemic growth combined with an aging population means Pennsylvania will "continue to lose seats and lose clout in Washington," Madonna added.

Trailing Florida

Pennsylvania, which trails only Florida and West Virginia in its percentage of residents over 65, had the 12th-biggest decline compared with other states in the under-18 population category, according to census figures for 2000 to 2009.

Pennsylvania officials project that by 2020, the number of residents aged 60 or older will increase by 9% to 2.6 million people, according to a state Department of Aging website.

That department oversees services offered to the elderly, including helping some 65-and-older residents pay prescription- drug costs and assistance in finding long-term care services. Pensioners also receive tax breaks from the state.

Cities For Seniors