CANADA:
Are Breed Bans Effective in Reducing the Number of Reported Dog Bites in a Community?
Winnipeg vs. Calgary
Winnipeg passed a breed ban against “pit bulls” in June 1990. While the number of reported dog bites in a city can fluctuate from year to year - it is clear that Winnipeg’s breed ban has had no appreciable effect in reducing the number of reported dog bites, especially when compared to other areas without breed bans.
Additionally, prior to the city’s ban on “pit bulls,” a young child died in Winnipeg from a dog attack. The breed/type of dog involved in the single documented fatality in Winnipeg was not a pit bull or pit bull-type dog.
The population of Winnipeg in 2007 was 653,000.
Calgary’s animal service by-laws have been and remain breed neutral. Dog attacks in that city are at the lowest they’ve been in 25 years, despite a steady population growth.
Calgary has effectively and significantly reduced the number of reported dogs bites from 621 in 1985 to 145 in 2008.
Not only have reported dog bites been dramatically reduced in Calgary, but aggressive dog complaints (includes chasing, biting, and damage to property) have decreased from 1,938 in 1985, to 340 in 2008.
The population of Calgary in 2008 was 1,043,000, almost 400,000 more than Winnipeg.
There is no documented case of a fatal dog attack in Calgary over the past 23 years.
***
Ontario:
In 2005, Ontario passed a ban on all “pit bulls” and any dog that may appear to be a “pit bull.”
Ontario claimed that pit bulls are “different” than other dogs and inflict injuries unlike other types of dogs. This claim was made, and the ban enacted, in spite of the fact that only one of Canada’s 33 fatal dog attacks (during the previous 45 years) had been identified to be a pit bull or pit bull type dog.
For the complete list of fatal dog attacks in Canada see: 
Fatal dog attacks_Canada
See the Canada Public Health Agency Study: 
Non-Fatal Dog Bites
National Canine Research Council