Which is good news, until you know only around 60% of the police depts. report to the FBI, none of Chicago's numbers are on there. Don't relax, it's a simmering pot, and could go into boil anytime once the benefits run out.
It also seems everyone is impressed how much the murder rate has dropped, but remember if you get medical help pretty quick your chances of survival go way up, note the very small drop in Aggravated Assaults, and those go under reported.
Murder is not the way to measure crime rates, but assaults are. Bullet wounds that would have killed you 20 years ago are survivable today, providing you can get medical treatment fairly quickly.