I cannot vouch for the accuracy of this information as it was quoted on a defensive handgun training video. However, in the the video, it was referenced that a study was conducted of the trauma results of handgun shooting incidents. The results were simply tabulated based upon the outcome (live or die). It was found that 97% of individuals hit only once by a handgun round survived the ordeal. And, 80% survival rate for 2 or more hits. I think that this speaks as much to superb trauma care after a shooting, than probably any thing else. There is much to consider in these numbers. Survival could mean many things, such as permanently disabled or alive but in a coma.
The point of the instructor in the video was that if you get hit during a defensive action, keep fighting as you have a very good chance of survival even if you are hit twice. Obviously, I would not recommend testing the results of the study.