I want to show that there is a lot more murder today than before because of guns.
I pick one year (a far edge of the bell curve type of year) to compare to today where there was the least amount of murders and compare it to day.
Without showing an average or showing even a distribution bias should be expected. There is very little reason for picking a single year to these types of arguments and it is too often done.
Anyway here's another source that shows that meat consumption has dramatically increased since the 1920s, though that wasn't my central point:
http://www.npr.org/sections/thesalt/2012/06/27/155527365/vis...