Until all police complaints become a matter of public record, it is literally impossible to assign a percentage to "rogue behaviors" or "rogue police."
You could also figure out the bad ones by those not coming in to do their job when they were being held accountable. Atlanta wants to defund the police, maybe? Fire the fucks who didn't come into work when they're now being held accountable. Government employees aren't that bad, but when they're given so much power they damn well need to be accountable. What an entitled lot. It was about 10% who didn't show up in atlanta. Show them the door and get a new batch and work on that culture.