I've killed nearly 150 Biggame animals with my own Bow (Hogs, Bears, Turkey, Elk, Caribou, Sheep, Deer, Buffalo) & been in on at least another 100+ blood trails (easy). I recall NOT finding 7 animals (2 Mule Deer, 1 Elk, 1 Hog, & 3 Whitetails). Of those we are guessing the Elk & 1 Whitetail & hog survived due to location of the hit & lack of any blood whatsoever. All Archery. I've never looked for a Gun shot animal.
Many years ago (guessing 70s) there were some figures published about the Necedah Wildlife Refuge in Ws. I beleive it was a 10 year DNR study & results showed 3% lost with Bow & 7% with gun. Don't hold me to that but those seem to be the figures I got from their information for an article when I wrote a informational sports/Bowhunting Column in the 70s.
I'm guessing a blind man that can smell will find more that 50% of shot animals. just a note though-I have noticed at a couple places I went Bowhunting that "some, a few" seem NOT to put a whole lot of effort into following up a difficult blood trail unless they have plenty of help.