What breed of dog bites the most people?
Statistically, the German Shepherd.
However, recording which breeds of dogs bite the most doesn't prove which breeds are the most aggressive. Most commonly talked about is the American Pit Bull Terrier.
Something else that needs to be noted, is that we can only give statistics for reported bites. In my lifetime, I've learned that you have a better chance of being bitten by a small dog, - ex., a terrier - and I use a terrier as an example because terriers were bred for efficiency in ratting, etc. in which the dog, obviously, used its mouth.
Just because a dog is of a certain breed NEVER means they are going to be aggressive. It's all in how they are trained, treated, and medically cared for.
I own a Pit, and she is a lover. She loves everyone, and other dogs and cats.

It is easy to say negative things about a Pit. However until you meet one that is raised to be a lover, and you have time to inter act with a Pit that is raised to be people and pother pet friendly, you will still keep your beliefs. That they are killers.

WRONG
Now if I only train my daughter.