Alot of that is a filter placed there deliberately. CSI 201 was a class with 2 500+ lecture sections and something like 30 lab sections. The graduating group for Computer Science had about 75 students.

201 weeded out the fratboys and folks who used "sort by first job starting salary" approach to picking a major. The 300 level courses washed out the people who weren't passionate/insane, and the 400 level courses taught you stuff.