I guess certain cities like NYC/Philadelphia might also push effective income tax to over 30% for lower incomes, but for the purposes of comparing income tax rates and capital gains tax rates in the US, it does not make sense to include the social security component of FICA or medical costs.
Edit: I am barely getting 30% in NYC, even including FICA (zip code 10118)
But yea it's probably top 10%.
If you include medical costs outside of FICA, which many other Western countries get for near free after taxes, then it looks... quite different.