Farmers, lumberjacks and fishermen have the highest suicide rate in the U.S., while librarians and educators have the lowest, according to a large study that found enormous differences across occupations. The study didn't explore the reasons behind the differences, but researchers found the highest suicide rates in manual laborers who work in isolation and face unsteady employment. High rates were also seen in carpenters, miners, electricians and people who work in construction. Mechanics were close behind. Dentists, doctors and other health care professionals had an 80 percent lower suicide rate than the farmers, fishermen and lumberjacks. Suicide is the nation's 10th leading cause of death. Public attention often focuses on teens and college students, but the highest numbers and rates are in middle-aged adults. Suicide is far more common in males, and the rankings largely reflect the male suicide rates for each group.