Anecdote: For several years, I worked closely with a rescue based in Flint, Mich - for most of that time I was vice president and so, very involved. I have no cite but while the ownership of pit bulls in the US as a whole might be about five percent, in poor ghetto-ish cities like Flint, I’d guess pit bull ownership is closer to 90 percent.
Anyway, the rescue I worked with did $10 vaccination clinics, usually right before dog licences were due and always in the “poor” parts of the city. You have to show valid rabies shot records to get a dog licensed, so it was both a benefit for the rescue and for people with limited funds to get their dogs vaccinated and licensed.
So, the vast majority of the dogs we saw were pit bulls. Often terrified (because they were not used to being off a chain/off their property) and often ill-behaved and untrained. On quite a few occasions a volunteer and a vet would have to go out to the owner’s car to administer the shot because the dog was too unruly to come into the PetCo/PetsMart that we held the vax clinics in.
We did five clinics that I helped with and they were well-attended; maybe about 2,000 or so dogs all told.
Of those, there were only two occasions of overt aggression towards humans. One was a husky mix who was utterly uncontrollable with utterly idiotic owners. That dog went for me and ripped a hole in the sleeve of my sweatshirt but thankfully missed my arm. The other was a poodle with painted toenails, cradled the whole time in the arms of its owner, that attempted to bite me, the vet, the vet tech and anyone else who came near it. I shit you not, the thing was a nasty little pirhana.
Not one of the pits or pit mixes were a problem although several tried to go after other dogs but we were pretty good about managing that sort of behaviour.
I’ve had Rottweilers in my life since 1985 and IMHO, like pit bulls, they are generally NOT dogs for people who want an “easy” dog or who don’t plan to put in quite a bit of time training, socialising and working with their family pet. While there are lots of exceptions (same with pit bulls), in general I would not recommend them to people who want an easy-going family dog. I’ve fostered quite a few pits and pit mixes and turned down a fair number of potential adopters because I didn’t think they were prepared to own a drivey-type dog.