Brick Underground article from 2014 which focuses on non-violent crime, uptown blocks only show up once and that is in the safest neighborhood category for Washington Heights. Most crime ridden neighborhoods in the city include, Soho, Meatpacking District, Williamsburg and Downtown Brooklyn. Harlem blocks appear to be somewhere on the average and are not listed
The above map is the most recent NYC crime map of which the city officially publishes by precinct for October 2015 and all of West Harlem is at the lowest end of the spectrum for being unsafe. Central Harlem and East Harlem even have lower numbers than many of the expensive neighborhoods like Williamsburg in Brooklyn while Midtown and Hells Kitchen are some of the worse spots in the city overall. Check out the full interactive map here: LINK
With all that said, crime is a factor living in the big city so all the good citizens out there should always be mindful of their surroundings and not take anything for granted.