Note that Franklin was the product of a society that had been executing felons for hundreds of years. The homicide rate in both England and New England in the early 1700s was around 2 per 100,000, lower than any western hemisphere country today.
If the population grew from 100k in 1700 to 300k in 1750, and if the homicide rate was right around 2 per 100k, then that would mean that the total number of homicides in New England, over the 50 years span was less than 300.
Do you really believe that fewer than 300 murders occurred during this time?
The FBI maintains murder statistics for most policing jurisdictions in the US. Many of them are under 2 per 100,000 per year: Sunnyvale, CA; Hercules, CA; Novato, CA, Brookline, MA; the Twin Cities. The rate in Beverly, MA, is 0.946.
