Women in the Labor Force: A Databook (2009 edition)
"The past several decades have been marked by notable changes in women's labor force activities. Women's labor force participation is significantly higher today than it was in the 1970s, particularly among women with children, and a larger share of women work full time and year round than in past decades. In addition, women have increasingly attained higher levels of education: among women aged 25 to 64 who are in the labor force, the proportion with a college degree roughly tripled from 1970
to 2008. Women's earnings as a proportion of men's earnings also have grown over time. In 1979, women working full time earned 62 percent of what men did; in 2008, women's earnings were 80 percent of men's.

This report presents historical and current labor force and earnings data for
women and men from the Current Population Survey (CPS). The CPS is a national
monthly survey of approximately 60,000 households conducted by the U.S. Census
Bureau for the U.S. Bureau of Labor Statistics. Unless otherwise noted, data are annual averages from the CPS. Users should note that the comparisons of earnings
in this report are on a broad level and do not control for many factors that can
be significant in explaining earnings differences. For a detailed description of
the source of the data and an explanation of concepts and definitions used, see the Technical Note at the end of this report."