What class are you in? A new Pew Research Center survey finds a third of Americans say they've moved into the lower class over the past four years.

"It's a big change for just a few years ago when 25% said they were in the lower class, today people self-identify themselves in that class at a rate of 32%" said Seth Motel, a researcher at the Pew Center.

The survey found not only has the lower class grown, but its demographic has shifted. People between the ages of 18 and 29 now place themselves in the lower or lower-middle class.

"Although the recession and the aftermath has hit the nation as a whole very hard, its hit the lower class especially hard" said Motel.

The survey also finds that hard times have been particularly hard on the lower class. Eight-in-ten adults (84%) in the lower classes say they had to cut back spending in the past year because money was tight, compared with 62% who say they are middle class and 41% who say they are in the upper classes.

Those in the lower classes also say they are less happy and less healthy, and the stress they report experiencing is more than other adults.

"They are stressed out about money and getting ahead, having and keeping a good job, saving for the future," said Motel.

As they look to their own future and that of their children, many in the lower class see their prospects dimming. About three-quarters (77%) say it's harder now to get ahead than it was 10 years ago. Only half (51%) say that hard work brings success, a view expressed by overwhelming majorities of those in the middle (67%) and upper classes (71%).

While the expectation that each new generation will surpass their parents is a central tenet of the American Dream, those lower classes are significantly more likely than middle or upper-class adults to believe their children will have a worse standard of living than they do.