See cheeseblubber's comment[1] which cites[2]: "With a crime rate of 54 per one thousand residents, San Francisco has one of the highest crime rates in America compared to all communities of all sizes - from the smallest towns to the very largest cities. One's chance of becoming a victim of either violent or property crime here is one in 18." It goes on to compare with NY[3]: "The chance of becoming a victim of either violent or property crime in New York is 1 in 40."
[1] https://news.ycombinator.com/item?id=35454781
[2] https://www.neighborhoodscout.com/ca/san-francisco/crime#des...
[3] https://www.neighborhoodscout.com/ny/new-york/crime#descript...