An argument that teacher salaries are low relative to alternatives careers is shown in the following table developed in a policy brief for California math and science teachers.
EdSource. (200. Math and Science Teachers: Recruiting and Retaining California's Workforce. Policy Brief/ http://www.eric.ed.gov/PDFS/ED499906.pdf
EdSource. (200. Math and Science Teachers: Recruiting and Retaining California's Workforce. Policy Brief/ http://www.eric.ed.gov/PDFS/ED499906.pdf