rawr!!!!! i go to washington and lee, the best greek school in the nation!! (well, number 3 is close enough, right?) it so rules! i loooove it! and one of my best friends from high school is a sigkap at elon! hooray greek schools!
my guess is, that they based the results on the surveys they conduct. at washington and lee around 80% of men are in fraternities. around 75% of women are in sororities. and 99% of the freshmen class goes through rush, even if they don't intend to pledge.