Crime, pretty much everywhere in the US and by many different metrics, has been falling for over 3 decades.
It makes sense. Crime is getting harder and harder to committ with the advent of the Internet and new surveillance technology. Crime is, like all things in life, a risk-reward calculus.
Most criminals aren't criminals because they innately like crime. Rather, they choose crime because they think the reward is worth the risk. If the reward falls, or if the risk is too great, many won't turn to crime.
With newer social services and things like the ACA, there's less reason to committ crime. You're often better off just... not... And getting help through provided channels. And then if you do committ crime, it's extremely likely you get caught, even for small crimes.