whoops, I presumed you were asking about the math. My source is nytimes which pulls from the dataset you linked.

https://www1.nyc.gov/assets/doh/downloads/pdf/imm/covid-19-d...

Specifically has numbers for NYC. You can sum the boroughs or use the total listed below. Using confirmed by pcr cases you get ~15k/8.6 = ~.175% as you said.

Using probable excess deaths adds an extra 5k deaths, hence ~.25%