State universities LIVE on this. Only an average of 18 students per class... but 90% of your classes are lecture-center classes with 300 students!
... that’s because “average class size” is reported from the point of view of the class, not the student. So, yes, there are loads of classes with less than 10 students... but your typical student isn’t going to be in them. Consider a university with 100 classes: 90 have 9 students, and 10 have 219 students. From the point of view of the class, 90% of the classes have less than 10 students, but from the point of view of the student. That’s the way the state universities frame it. But from the point of view of the student, more than 70% if the classes have more than 200 students.