From Bureau of Labor Statistics [PDF]
In 2010, women who were full-time wage and salary workers had median weekly earnings of $669. Women earned 81 percent of the median weekly earnings of their male counterparts ($824). In 1979, the first year for which comparable
earnings data are available, women earned 62 percent of what men earned. The women's-to-men's earnings ratio has been in the 80 to 81 percent range since 2004; prior to this time, the ratio had been gradually trending upward.