I can comment based on my observation (lately shared by many) that most of the medical literature is bunk and my experience participating in more than 100 autopsies which tells me that 30% is absurdly high, 15% is too high and the range reported is bizarrely large. In those over 100 autopsies I recall only two surprises. Mostly we learned nothing the clinicians didn't know. Occasionally we found something unknown that wouldn't have altered treatment or course. My experience was that the autopsies were overwhelmingly uninformative.