The General Social Survey -- the most comprehensive exploration of U.S. job satisfaction and happiness -- found the happiest and most satisfied U.S. workers were clergy, with 87 percent very satisfied and 67 percent very happy.
The least satisfied were roofers, with 25 percent finding job satisfaction. Garage and service station attendants were the least happy, at 13 percent, the study found.
"The most satisfying jobs are mostly professions, especially those involving caring for, teaching and protecting others and creative pursuits," survey director Tom Smith said.
Across all occupations, an average 47 percent of people said they were very satisfied with their jobs and 33 percent said they were very happy.
After clergy, firefighters and physical therapists were the most satisfied. On the happiness scale, firefighters and reservation agents were the happiest.
After roofers, low-satisfaction jobs included waiters and bartenders and hand-packers and packagers, the study found. The least happy, after garage and service station attendants, were roofers and molding and casting machine operators.
Researchers interviewed 27,587 people nationwide in person from 1988 to 2006 to come up with the results. The margin of error varied from 3 percent to 8 percent based on the number of people in specific occupations.