More like what percentage don't... I don't think I have seen a doe that doesn't have horns. They aren't very big, anywhere form an inch to 4-5 sometime, but really thin and straight.
I haven't noticed many with horns. I live in Eastern WY, and I've only noticed a few with horns. Last years hunt I was looking for one with and didn't see any when I had my rifle in hand. I ended up shooting one without. Where do you see your goats? mateo