Now that's a good question and deserved real attention.
I started hunting deer when I was a young boy with my dad. He let me shoot some of the deer he had tags for and so did my mom. I have been shooting deer and larger game now for 53 years. I started hunting game larger then deer when I was 17, so that's been 44 years. I can't count the number of game animals I have killed ------ and I probably could have said that when I was 30years old. I am now 61.
I have killed game with a lot of rifles and 11 different handguns that I can recall as I write this, as well as 3 different bows with wood arrows and one deer killed with an aluminum arrow.

An honest guess would be that about 60-65 percent of my game has been killed off-hand.
The other 40% is divided in categories of Standing-Rested (like a tree branch or rock) sitting, a few (probably 10) kneeling, and at least 40 prone or prone over a back-pack. I also remember killed 3 deer resting over an open door of a Toyota Land Cruiser.