From the WSJ, this story claims that just 29% of Americans say they're "very happy." (Thanks, Aldis!)
Excerpt:
"The Declaration of Independence enshrined the pursuit of happiness as an inalienable right. Lately, that pursuit appears to have gotten more difficult. The General Social Survey, out of the University of Chicago, polls U.S. residents on everything from how often they attend church to how much they trust one another. In the latest poll, the number of people who said they were "very happy" fell to 29% last year. That is down from 32% in 2006, the year before the recession started, and the lowest level the survey has registered in its 39-year history."