(Bloomberg News) In Tiffany Spaulding's 12 years in the pharmaceutical industry, she's worked for three companies, two of which no longer exist, and relocated to four states.

Now 39 and living in Brookfield, Connecticut, she hasn't had a promotion in five years and says she sees no chance to advance, stuck behind a wall of baby boomers. She would quit and turn her hobby of jewelry design into a business, she says, if not for the home and school loans that eat up half her salary.

Spaulding, according to a new report, is a typical member of the relatively small group called Generation X, 46 million Americans born between 1965 and 1978: They're ambitious, squeezed by debt and frustrated by people who aren't retiring on schedule. More than a third hope to leave their jobs in three years, a survey of more than 1,100 members of Generation X by the Center for Work-Life Policy found.

Twenty-eight percent say they are working longer hours, an average of 10 more a week than three years ago, and credit card debt helps dictate career choices for 74 percent, according to the center's report, based on research including interviews with Spaulding and 200 others.

"They are being leaned on from all sides," says Sylvia Ann Hewlett, a co-author of the report and the founder of the center, based in New York. "They don't think that there is necessarily a clear set of opportunities ahead of them in corporate America, so there is a lot of flight risk."

The group's moniker was popularized by Douglas Coupland's 1991 novel "Generation X: Tales for an Accelerated Culture," and its members were epitomized as apathetic and directionless in films such as "Slacker" in 1991 and 1994's "Reality Bites." They long ago shed that image, Hewlett says, and as they approach middle age pose challenges to companies that need "bench strength for leadership."

They have different expectations -- and demands -- of employers, according to the report, prizing independence and flexible hours more than their predecessors.

While their experiences and complaints are shared by other generations, the report says that for this group, trends such as the rising cost of higher education have hit particularly hard. It says those entering college in 1996 had average expenses more than four times higher than boomers 20 years earlier.

Many began their careers as companies started cutting back on pensions and health care benefits, and while people in Generation X are more educated and more diverse than boomers, they have had "no welcome in the economy," says Neil Howe, a demographer and co-author of six books on generations in the U.S., including 2010's "Millennials in the Workplace."

'Financial Disaster'