At the rate Aids is going, it won't be long before most intraveneous durg users and most of the gay community are dead. Most of them will not change their ways. What a shame, but they do have a choice.
Most of the decline in crime rate is not due to better policing, prosperous economy and all the other BS that politicians like to take credit for. If you run the numbers on how many drug addicts die from AIDS, plus the number of ex-prisoners who die from AIDS, and make some reasonable assumptions about how many felonies are annually committed by each drug user or felon, the dead AIDS victims easily account for the decline in the crime rates.