I found this article on the cdc website. The data is from 79-96 but it is a report of the number of deaths attributed to dog attacks broken down by breed, where the breed was able to be determined.
A couple of points about the CDC study. You will notice "Pit Bull" is in quotes (as are Huskies) this was because this name was used to represent several breeds under one name. With 'Huskies' It was Alasken Malamutes and Siberian Huskies, two closely related, but silimliar breeds. With "pit bulls' it was American Pit Bull Terriers, American Staffordshire Terriers, American Bull Terriers, English Bull Terriers, and American Staffordshire Bull Terriers. All closely related, but different breeds. The umbrella term 'pit bull' in the CDC study actually represents 5 different breeds, which brings me to the second point about the CDC study. You notice it is dated 1997? Do you know why there isn't a 'newer' one? It's because the CDC determined that dog breed was often both inaccurately reported and/or confusing to the whole issue, which was actually more related to things like how the dogs were kept, the reproductive state of the dogs in question, etc.
There are an average of 20 human fatalities per year attributed to dogs. That number remains pretty constant, although the breeds responsible change over the years, depending, mostly, on their pervasiveness in the community. Ie. more dogs of X breed in the community make it more likely that X breed will be involved in a fatality.
Did you know you are 151 times more likely to drown in your own bathtub then to be attacked and killed by ANY breed of dog? Although drowning in your bathtub doesn't quite elicit that same visceral fear response does it? You are more likely to be killed by a falling coconut then killed by a dog, yet people seldom freak out when walking near palm trees.
Your child is over a 100 times more likely to be killed by choking on a balloon, that symbol of childhood, then to have a fatal encounter with ANY breed of dog.
As a concerned parent, you are best served by teaching your child how to interact with dogs. Not to approach strange dogs (especialy chained) not to pet dogs without asking permission from the owner. How to stand like a tree when approached by a strange dog, rather then 'acting like food" (prey) and running and/or screaming, which will often stimulate an otherwise non-aggressive dog to chase.