What about the PQ terrorists? And as pointed out, the homicide rate was three times higher back then. 

Today, cities with a higher percentage of immigrants (Toronto, Vancouver, Montreal) suffers from a much lower crime rate than cities with a higher percentage of non immigrants (Winnipeg, Regina, Edmonton, etc). The reason for this is that there are less single parent families among immigrants. Most of the crime in North America is done by a male between the ages of 15 to 30 years old who was raised in a single parent home. 

Most teenage pregnancies are carried by girls who grew up in single mother families. Immigrants are much less likely to suffer from these social afflictions, and therefore their kids are likely to be better off than their parents. Many Canadian born kids, on the other hand, are returning to their parents basements after graduating from University.