The first gun accident I recall on a set was the Hexum death I the 80s. I wonder how often it has happened before that? The sheer number of guns fired before that in TV and film is immense.
Just guessing but my guess is in the millions.
They do a lot more dangerous things on movie sets than firing blanks from real guns. And 99.9% of the time no one gets even a scratch.
The death of Eric Fleming (Rawhide) lead to having stunt doubles do more dangerous scenes. He drowned when boat tipped over while in rapids. Took several days to find his body.