21. Dental hygienists
Projected increase in 2020: 37.7 percent
Number employed in 2010: 181,800
Median pay in 2010: $68,250
Education/training: Dental hygienists must get a state license to practice. A degree from dental hygiene school is also usually required.
Job outlook: The demand for dental services will grow because of population growth, older people increasingly retaining more teeth, and a growing emphasis on preventative dental care.