when we toured Dartmouth with my son in 2014, I recall that they said that something like 75% of upperclassmen, so that’s in line with you @Faulkner1897. That was a big reason my son did not apply there, as he wasn’t interested in Greek life. As a side note, a family friend went there and hated the party-greek atmosphere and left after one quarter. She waited out the year and entered as a frosh at another school she was accepted at (MIT) and was much happier there.