I hadn't done any in years, but I managed 20 last night while leaving some in the tank to not tax arms that haven't had much load bearing exercise in a while.
Seems like 20 reps is basically my default floor. In my teens I would do 20 reps regularly. During grad school I maxed out at about 65 following the 100 pushups training plan before losing interest. That was maybe a decade ago. Picking up cycling a year ago doesn't seem to have affected my pushup ability.
My dad turns 70 this year. Last year he decided to work toward 100 pushups, just by doing them whenever he felt like it througout a day, and he actually did. I forget what he started out being able to do, maybe 20-30.