My friend, who went to Cornell in the 90s had over 300 in her house. There were 23 houses on her campus at that time. You can do the math.
As far as NPC sororities, Cornell has only chartered 18 NPCs in its entire existence. The most it had on campus at any one time in the 1990s was 14 NPC chapters. I'm from a large midwestern campus (University of Illinois) so I get your point, though.
__________________ Adding 's does not make a word, not even an acronym, plural