So I was doing a medium run going to floor 100 and getting all possible achievements in the process and by the time I got to Floor 100 I didn't unlock the BONK! achievement (the one where you have to get hit by a chair 100 times) so I was wondering...

Does the game track how many times you get hit by a chair per run or is it cumulative and saves based on ALL your runs?

As far as I know,
it should be cumulative.