Around here (California) they go up and down with the budget. So when DD7 started kindy it was about 34 at the school down the street, a big factor in our going to the charter she got into, which caps firmly at 20 for kindy, 22 for 1-2 and 24 through eighth grade. The local schools are lower now but still can't compete with that (I've taught high school here and we had upwards of 40 in AP courses and yes the essay grading and time limit on things definitely hurt the experience.) We have a small school, too.