http://www.nytimes.com/2010/02/07/fashion/07campus.html

Pay special attention to this part:

Jayne Dallas, a senior studying advertising who was seated across the table, grumbled that the population of male undergraduates was even smaller when you looked at it as a dating pool. “Out of that 40 percent, there are maybe 20 percent that we would consider, and out of those 20, 10 have girlfriends, so all the girls are fighting over that other 10 percent,” she said.

There you have it, straight from the horse's mouth. All the single women on campus are chasing the top 10% of men. What's even more telling is how right off the top, despite men being in the minority, a full half of the men in her field of view were dismissed out of hand.