That number doesn't really matter, does it? I'd think the average number of people there each day is much closer to the relevant number.
Yes, and that "average number of people there each day" would include all the non-residents/tourists in the city. Which is a non-trivial number at all for NYC.
So if there really is an 11x increase in crime, along with a 10x increase in yearly population, that's actually a huge increase in crime on a per-person per-day basis.
Correct, but NYC had 66 million visitors in 2019[0], which is way more than 1mil you guesstimated.
Which, conversely, would increase the daily population by 20k*66=1.32mil. 1.32mil is a non-trivial increase in daily population at all.
0. https://www.osc.state.ny.us/reports/osdc/tourism-industry-ne...
I'd also factor in the numbers are higher also because policing is very robust. I can't think of any other city where I saw a cop nearly as often as NYC, they're everywhere.
Anecdotally, I never felt unsafe there. Although where I grew up crime was rampant, common, and expected- so comparatively NYC seemed really safe, and it wasn't hard to avoid high risk places/situations. I do think people hype up the crime numbers, and forget to consider the variables present in a megalopolis which aren't present in smaller cities.