The statistics they cite are as follows:
I wrote about this issue back in 1999 in an essay entitled, appropriately enough, "Women and Work." Drawing on economic theory, contemporary labor statistics, and earlier work done by Thomas Sowell in his Civil Rights: Rhetoric or Reality?, and , I concluded
Working women are paid just 77 cents for every dollar their male counterparts receive. Although women earn 57 percent of bachelor's degrees and 60 percent of master's degrees, they continue to represent a meager 3 percent of CEOs in Fortune 500 companies, hold just 15 percent of the board seats of those companies and fill only 6.3 percent of top-earning executive posts.
[T]he performance of women's earnings over time is not the result of systematic discrimination. Whether egalitarians like it or not, for the "average" woman her family life trumps other concerns on the margin. Employers and employees are merely recognizing this fact of nature: women and men are not equal in the sense of being identical. They are different and have different comparative advantages when it comes to work outside the home versus child rearing.
Of course, both men and women would like to work for much more than what they are getting paid, other things equal. But then, the other things are never equal. That fact serves as a useful devise for egalitarian politicians and bureaucrats. Social engineers use the persistence of inequality of income as the warrant for never-ending regulation.
I have no reason to conclude differently this time around.