Keep in mind that my school only has 4 periods so taking 3 per year is pretty much the max for anyone.
Freshman year - None. It's impossible to take an AP as a freshman at my school due to prerequisites for the AP courses.
Sophomore year - AP Chemistry
Junior year (currently) - AP Biology, AP Calculus AB, AP Calculus BC
Senior year (planned) - AP Statistics, AP English Language & Composition, AP Chinese