I don't think there is any way to really say for sure. Maybe someone else has a better handle on your question.
Cultivated roots seldom are allowed to grow for seven years. Most are harvested at four, earlier if they start to disease, and a year or so later if they are growing well without disease issues in the garden. I have a picture of one root that was bigger than a $20 bill I put next to it. That is not very uncommon for four year old cultivated roots either.
Talking wild, we have mixed ages from 7-80 years or so, and some years the average per pound is better than in others. Last year, the wild ginseng I certified averaged about 150 roots per pound if memory serves. I have heard and seen lots where the average count would be double that.
If you are talking woodsgrown root that is not fertilized, they will appear in all aspects to be wild and have similar weights.