Here is the data for % white, % black, and murder rates in NYC by decade, from 1960 through 2010.
Second thing to notice: The black population % fell only slightly since its peak in 1990 (from 28.71% to 25.55%).
In 1980, when the murder rate was FOUR TIMES as high as in 2010, the white population % was slightly higher, and the black population % was slightly lower, than in 2010.
Don't let racial stereotypes eat your brain, folks! Always look at the data. (end)