IN the late 80's and the 90's I must have hit at least 6 different bucks in the shoulder blade. (back then I was shooting with a finger tab and no sights.)

NOT ONE of those bucks was ever found, nor were there ever neighbors reporting of finding a dead buck with a shoulder wound.

Since I got a new bow in 2002, I shoot w/ release and sights, and I tend to aim farther back and quartering away. However, last year, I shot a doe, and the arrow exit THRU her far shoulder blade. It got stuck about 1/2 thru, but by then, it had already hit the lungs.

To answer your question...my experiences have been that SHOULDER blade hit deer are many times lost due to lack of blood, or the fact that it does not kill the deer.