This report by the Vera Institute is extensive and thorough. You need to open the link and check it out!

Topics include:

How many arrests are made annually, and for what?

How do arrest trends vary across demographic groups?

Clearance Rates
How successful are the police at solving crimes?

How common are victimizations, and to whom are they reported?

Data Reported
What gaps exist in policing data and why?

The Charts and All the Info!