Your example here does indicate that all cops aren't bad. Unfortunately it does seem that good cops are the exception, not the rule. How many of the brethren that may not have participated in this instance, did know about it, laugh about it, and turn a blind eye?From the story. Another cop found out and brought it to light, pursued charges and made the arrest.
So that means ALL COPS BAD!
Percentage wise....how many officers are blatantly unfit for the job? How many are honest enough to police their own?
You'd likely have a hard time convincing anyone that it's anywhere close to an even percentage.