Much has been made of the idea that the United States is falling behind global competitors: Manufacturing jobs are disappearing, there is more of a focus on academics in Asian schools and now, according to a United Nations report, we also don't work very hard.

Fortune's Geoff Colvin writes that only 18% of American workers put in more than 48 hours per week, which is better than the Netherlands, Norway and Japan. But workers in developing countries are, predictably, putting in a lot more hours. In South Korea and Peru, 50% work more than 48 hours. Meanwhile, Americans have more leisure time than ever. Colvin writes that "researchers figure we're getting about 117 hours of leisure per week (including sleep), vs. 110 hours in 1965. That's more than 360 additional idle hours per year. We are a couch-potato nation."

What's disappointing is that, with all that free-time, Americans aren't really improving themselves. People are fatter than ever before, and few people read frequently. Are we devoting an extra 360 hours per year to eating junk food and watching reality television? If so, can that really be called a quality of life improvement?

But maybe there is some silver-lining here. With many Americans suffering with large debt-loads and subprime loans, this study may point to the answer: Perhaps people should just work harder.