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.
https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=351000...
I also have to doubt the accuracy of such data collected in the 1700s.
There are many sources online that agree, so I won’t bother to link them, that the population of New England was ~100k in 1700 and ~300k in 1750.
The claim that that actual rate of murder in all of New England was 2-6 per year is not believable.
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.
Japan's rate is 0.4.
The population reached ~300k in 1750. A murder rate of 2 per 100k times 300k people equals 6 murders. Multiply that by 50 years to get 300 murders.
This doesn't affect my 2nd and 3rd paragraphs though.
It was a violent time.
Just one 'dataset': https://en.wikipedia.org/wiki/List_of_Indian_massacres_in_No...