From the earliest tickle experience you can remember, how many people have you tickled in your life. Every tickle counts...extended tickle torture sessions, brief little pokes, inadvertant tickles!
51-100, if we're counting playful tickles. I think I got every girl I knew in high school at some point or another, and almost all the girls I know at college. Sadly, most of them lasted no more than a few seconds, but hey, it counts