WASHINGTON – As the nation struggles with the aftermath of the Great Recession, few groups have suffered greater setbacks or face greater long-term damage than young Americans — damage that could shadow their entire working lives.

Unemployment for 20- to 24-year-olds hit a record high of more than 17 percent earlier this year. Even for young adults with college degrees, the jobless rate has averaged 9.3 percent this year, double the figure for older graduates, according to the Labor Department.

Adding to the impact, surveys by the Pew Research Center indicate, a greater share of workers in their 20s lost hours or were cut down to part-time status than any other age group. And their incomes have fallen more sharply, even as they are far more likely than others to say they are working harder than ever.

“These are young workers just trying to establish a connection to work, and it will cause permanent damage to long-term pay. This crisis has the potential for scarring,” said Ron Blackwell, chief economist at the AFL-CIO.

The effect of the recession is reflected in the fact that many young Americans who started out living independently are moving back home with their parents because they are unable to survive financially.

Also, new Census Bureau figures show that couples increasingly are postponing marriage and parenthood, waiting for their financial prospects to improve. Meanwhile, more young families are falling into poverty.

“It makes you almost want to cry for the future of our country,” said Andrew Sum, director of the Center for Labor Market Studies at Northeastern University in Boston.

HARBINGERS OF PAINFUL CHANGE

These developments, beyond their effects on individuals, are harbingers of significant and painful changes for the whole country.

For decades, adult life, especially for college graduates, began with entry-level jobs that paid well and promised even better things to come. Those bright prospects encouraged young workers to go out on their own, marry and start families — bolstering the overall economy.

But now, with so many unemployed or underemployed — and others underwater on their mortgages or with little hope of buying houses of their own — the spending they once provided simply isn’t there now.

Moreover, low starting pay means that future earnings probably will be depressed as well because most workers see their incomes increase slowly and steadily over the course of their careers, not in big jumps.

In the near term, young adults’ lower earnings and slower rates of family formation will hurt the still-depressed housing market and crimp consumer spending, which accounts for 70 percent of the U.S. economy.

In the long run, it could shape the way a whole generation saves and invests, with far-reaching consequences for businesses and the economy.

Young adults, for example, may be less prone to buy stocks because they have been shell-shocked by the recession, said Mark Zandi, chief economist at Moody’s Analytics.

He recalled how when he encouraged his own college-age son to put some money in the markets, the advice was met with incredulity. “It dawned on me,” Zandi said, “that’s his world. In the last 10 years, stock prices have gone nowhere.”

Young adults remain very hopeful that things will get better, surveys show, but many face daunting debts that are forcing them to further curtail spending now.

In the two years before the recession, adults younger than 35 were borrowing so heavily — especially for education — that their savings rates ran in the negative teens, according to Moody’s analysis of Federal Reserve data.

Since the middle of last year, they have become the most prodigious savers of all age groups, socking away 8 percent or more of their after-tax incomes.

“We need them to drive housing demand and consumer spending,” Zandi said.

With less means, the share of the population 18 and older that is married was just 52 percent last year — the lowest in more than a century.

“Marriage is becoming more and more for those who can afford it,” said Mark Mather, a demographer at the Population Reference Bureau, a private research group in Washington.

“These kinds of social changes tend to be glacial, but they’re happening quickly,” Mather said.

MANY DELAY MARRIAGE

Mather said the recession prompted even more young adults to delay marriage.

There has also been a rise in the number of children being born into unmarried households, which analysts see as an ominous social and economic development, given the high poverty rate for children and families in such households.

Yet despite all the indirect effects of the recession and the ongoing difficulties in the job market, surveys show that young American adults, as a group, are strikingly optimistic about their prospects.

“It’s a generation that seems to feel empowered by technology,” said Paul Taylor, Pew’s project director. Pew found that of people ages 18 to 29, three-fourths had created a profile on a social networking site and 1 in 5 had posted a video of themselves online.

Kelli Imdieke, 24, believes things will turn upward, though lately she’s begun to have doubts about the long term.

She graduated from the University of Wisconsin-Eau Claire with honors in December, receiving a degree in mass communications. Since then, she’s been turned down for openings in advertising and marketing, and is even struggling to get more hours in her part-time job as a waitress in the Minneapolis area.

At the moment, Imdieke is living rent-free at her mother’s friend’s home, and she makes enough money to cover her personal expenses. But with college loans to pay off, she is becoming more concerned about a prolonged setback to her finances.

“I’m pretty optimistic,” she said.

But after being surprised by how much worse things have been than she imagined, Imdieke has lowered her sights too. She doesn’t see her generation enjoying the prosperity their parents did.

“It was a great period,” she said of the economic growth as baby boomers were coming of age. “People were coming home, having babies, building homes. I personally don’t think it’ll happen in my lifetime.”