I would add that you have to adjust for age-related criminal activity.  The crime rates everywhere rise and fall in direct proportion to the age 14-24 population group.  When this group has access to free or very affordable education and work with reasonable compensation crime levels drop. 

Or we can follow California's ingeneous Prop. 13 example and substitute prisons for schools.

http://www.pbs.org/newshour/rundown/chicago-35000-people-murdered-50-years/