This is research by Paula England who is a professor of sociology at Stanford University.

http://www.mediaed.org/assets/products/244/studyguide_244.pdf

The specific graph is on page 14.

A common thread on the red pill seems to be that women have much more sex than men as it is far easier and they are the gatekeepers.

If this were true I would assume that men's median hookups would be lower than women's but it turns out that the reverse is true.

How do you explain this?