20 years ago there was this app on windows which measured how many centi/meters you moved the mouse on a day - and it had a longterm counter which was never reset :-D
I have no way to even estimate that.
I've used whatpulse on macOS, but it's intrusive in terms of permissions/license/etc. I tried a couple other open source keystroke loggers, but they were out of date.
Linux/windows might have better options, but I haven't checked.
I could have stated that more clearly. I'm aware that there is software I could install to track this. I was just saying that (like, I imagine, the vast majority of people) I haven't installed such software, so don't have any basis on which to even hazard a guess.
I could certainly install such software, but have no need to do so.