[wccrawford]

I went to school in a rural area of the US and we also had about 20 kids in most classes. It started to get a little more crowded towards high school as there seemed to be a lot of people moving to the area and it didn't seem to be expected. But everyone was worried there were too many kids in class when there were 30 at that point.

So I think this varies quite a lot across the US. I tend to feel that large cities have more crowded classes than rural areas, but I have no data for that.