For me (and I do not blindly follow any agenda ever) I look to Chicago as they have had some of the strictest gun control laws in place for the longest period of time that I am aware of. That allows for it to be the most usable tracked data.

 By the way, I really like Chicago. My spouse is from there. Diehard Cubs Fan before it was cool to be one. Our child's namesake is born and raised and current Chicago!

 But the gun laws have not changed the criminals 'kill' rates by guns. If anything, it has increased. 

 So that is why I watch it and use it. I may live long enough to track CA next.