As I noted in the discussion of the last post, the data I presented is from feminists.  Specifically, Infoplease states that the source of the data I used for the chart on the previous page is from The National Committee on Pay Equity (NCPE):

Source: U.S. Current Population Survey and the National Committee on Pay Equity; also Bureau of Labor Statistics: Weekly and Hourly Earnings Data from the Current Population Survey.

What is the NCPE?  From their about page:

The National Committee on Pay Equity (NCPE), founded in 1979, is a coalition of women’s and civil rights organizations; labor unions; religious, professional, legal, and educational associations, commissions on women, state and local pay equity coalitions and individuals working to eliminate sex- and race-based wage discrimination and to achieve pay equity.

NCPE’s purpose is to close the wage gap that still exists between women, as well as people of color, and men.

Since the data I presented had the problem of comparing the “wage gap” for all women in 1963 with later figures for White women, I decided to see if the NCPE had a time-line for all races going back to the period prior to the passage of the Equal Pay Act.  They do.  Here is the full time series they present in chart form:

Note the 17 year period between the implementation of the Equal Pay Act outlawing wage discrimination by sex and the beginning of the increase in women’s earnings relative to the earnings of men.  Feminists are telling us that after this law went into effect nothing changed, and I’m inclined to believe them.  Here is a chart showing just 1960 to 1980 for more detail (the Equal Pay Act went into effect in 1964):