There is no doubt in my mind that dogs can and do kill people every year, and my heart breaks for bite victims.
Fortunately, the numbers are very small compared to both the sheer number of dogs in this country- as well as the many ways and means people are killed every year in this country. DBRF's average about 35 a year- for a population of 312+ million people- in which more than 55% of households had a dog (and that's not counting strays!)
The CDC ran a study that spanned 20 years (beginning in 1979) in an attempt to identify breeds most often reported in dog-bite related fatalities. Pit bulls and rotties (and mixes thereof) took the top two spots.
http://www.cdc.gov/HomeandRecreationalSafety/images/dogbreeds-a.pdf
It should be noted that most fatalies from dog bites are incured by babies, toddlers, small children, and the elderly. Why? Because they're the most vulnerable to injury- and in the case of babies and small children- they are often unsupervised and prone to making sounds that 'excite' dogs.
All dogs are capable of biting and killing.
But the odds are really in our favor- and they increase drastically with proper ownership, and responsible care and training.
I have no doubt in my mind that our beloved pitbull mix would
never bite a human- and in fact she's done her fair share of helping find them.
But I wouldn't leave a baby or small child unattended with any dog, either. It's no different to me than giving a three year old a gun and assuming they're not going to get hurt.
It's all about responsibility.