I’m about 40% prone, 55% sitting and 5% standing. The first decade of hunting it was more like 60% 15% and 25%.
I lost a bear that I hunted hard a couple of years for because I went prone on an easy 200 yard shot and discovered a slight rise preventing the shot - got up into a sitting position just in time to watch him walk into the trees - one of my three all time top hunting regrets. Since then if it’s under 300 yards I automatically sit first - Bang Bang! For me, sitting with a knee strap is good to 350ish and a tall bipod and knee strap will reach out to 375 yards. I’ve been impressed with the range guys are getting with a pack wedged on the chest - it’s never worked for me, but I most likely haven't practiced with the pack enough.
In the early years I figured if it was 125 yards or less, offhand was the fastest shot - that’s true for the most part, but with practice, dropping into sitting is nearly as quick, and the more you practice the faster you’ll be, so my standing numbers have gone way down. Nonetheless, sometimes there’s no time or clearance for anything but a good old standing shot.
Most of my friends hate practicing seated, so they also avoid it in the field. The ones that do, practice it much less than they should. 10 minutes of practice a day, even if it’s dry firing, will more than double a new shooter’s hits.
I just went through my camera roll and only counted the ones I could remember and I was present. I am way out of the norm here.
Prone-8
Sitting-5
Kneeling-1
Standing-40
Supported-21
Unsupported-33
Farthest shot on this list was 890 yards closest was 11 yards. Most were well under 150 yards. I counted anything touching the gun other than your hands, shoulder, and cheek as being supported. Be that a tree, bipod, tripod, backpack, shooting sticks, etc.