RE: How do you define a "top end".....
Where my house is and I do most of my hunting I would define top end as the top 1% of the bucks taken in my area. I can't say what % of mature bucks taken because there really aren't enough mature bucks taken every year to know. Most people around here are "buck" hunters. Nothing wrong with that, but it makes it difficult to compare.
I live in Preble county Buckeye, and I am sure you are aware that we are one of, if not the lowest producer of "trophy" bucks in the state. However, if a buck here could live to see 4.5 or 5.5 I guarentee that he would be an absolute brute. It is just so seldom that they are able to live that long. I would say in 22 years of hunting here, and my father more like 30, we have seen a total of 10-12 bucks that were in that age group.