There are so many factors, it's really a tough question to answer. If the seed is good, and you plant it where other seng is already growing, and there are no deer/turkey/squirrels/slugs to bother it, and the weather is good for 10 years, and there are no fungus or disease present, and no poachers find it, and they don't log out your woods, you could probably get 80% or higher. But it's not likely you'll find a location like that.
I'm not trying to be a jerk, I just wanted to point out how many stars need to align to get ginseng to grow.
25% is probably high for 10+ years, maybe if you dug in 6-8 years. I think it is more in the single digit to low teen percentage. I consider wild-simulated to have no fungicides,chemicals,pesticides ever. but others have their own ideas on what wild-sim should be.
Furbearing pests seem to be minimized by normal country gardening methods. A few tin can alarms, some scattered dryer sheets, a sprinkling of human hair and the frequent scent of cordite do wonders. Turkeys though have overrun the area and seem to be deterred only by my dogs or the generous application of bird shot. A friend suggested a battery radio on a timer or motion sensor, I think I will try that this fall.