I’m in a regular, public high school with limited AP choices, but by the time I finish school I hope to take 12-13 APs (possibly 14 or 15, but just exams and not classes). I’m a sophomore and I’ve already taken 3, I’m taking 4 or 5 more next year, and my senior year is going to be solely APs (and possibly dual enrollment if I have to).
the typical student in my school probably takes 0-1 AP, and if they do take that 1, they drop out. most of the people in my AP classes only shoot for around 10 APs at the most, but typically they take 1-2 each school year (excluding freshmen year, but there are some who choose to do AP human then).
Of all the students who took AP exams in 2015, 79% took one or two exams (see [this PDF](https://secure-media.collegeboard.org/digitalServices/pdf/research/2015/Number-of-Exams-per-Student-2015.pdf)). So the average number of exams for all high school students is probably zero or one.