No...I have no idea how to find the relative proportions of semi-automatics (does that include revolvers?) to single shots.

However, Violent crime in the U.S. has fallen sharply over the past quarter century. The two most commonly cited sources of crime statistics in the U.S. both show a substantial decline in the violent crime rate since it peaked in the early 1990s.

Contrary to the impression given by the mass media.

Also there's a difference between mass shooting and mass killings.

ruby ridge, the oklahoma bombing, 911 come to mind.

there are 'about' 300 people who die from mass shooting in the US a year.
there are 'about' 300 people who die from medical errors in the US a day.

does that help?