Number of deaths in NYC divided by total population is 15,000/8,000,000. This already puts the fatality rate at at least 0.2.
But the consequences are far from over and the number of deaths will keep climbing, so your "fatality rate may be as low as 0.10-0.20%" is completely off the mark.
edit: I am sorry if my tone was interpreted as confrontational. I otherwise agree with the parent's post that we need much more antibody testing.