There’s a reason why the expression is “a rotten apple spoils the barrel.” An unchecked corrupt individual is indicative of - or causes, by being unchecked - a systemic problem. It’s “funny” how often the “bad apple” metaphor gets used unironically by police forces (and their apologists) who try to use it to indicate the lack of a systemic problem.
The answer is almost certainly “most of them.” However many that is…
Yeah, at a minimum. Right now we’re only catching the idiots who don’t know how their camera systems work (that they’re constantly recording, but throwing out all but the last minute of video until the cop hits the record button). However, I also fear that once cops get used to them, they’ll be playing to the camera even more than they are now, staging little fictions made possible by the fact that they still have some control over what it sees, even if they can’t edit it.