General Discussion
In reply to the discussion: Footage reveals U.S. police shooting homeless man 46 times [View all]sarisataka
(22,710 posts)most of the research on this comes from the book On Killing: The Psychological Cost of Learning to Kill in War and Society by Dave Grossman (an excellent book which I strongly recommend to anyone with an interest in the subject)
The site you reference below summarizes many of the points Grossman makes. In WW2 the rate of troops effectively engaging the enemy was between 15-20%. The rest would either intentionally shoot to miss or volunteer for jobs to keep them from having to shoot e.g. caring for wounded, retrieving ammo etc.
Since this phenomenon was discovered training has been altered to counteract the natural inclination to avoid killing. In Korea the estimate is 55% would effectively engage and by Viet Nam the number was 90+%.
I have not seen more recent numbers but my experience is that the percentage is still very high.