Couple problems.
Pit bulls are more or less the canine equivalent of assault weapons. The definition of which breeds are included is very loose. Often means any large scary dog.
Statistics on dog bites are collected with a very wide degree of reliability.
Any statistic as to number of bites or deaths caused by a particular breed is pretty meaningless without qualification by number of those dogs of that breed in US or percentage of dogs of that breed.
IOW, if (to make up some numbers) 25% of fatal bites are by “pit bulls,” but pit bulls are only 1% of all US dogs, they’re a lot more dangerous than the raw numbers or ranking would indicate.
From the site www.dogsbite.org
Pitbulls: 263 deaths
Rottweiler: 81 deaths (next closest)