I've never counted how many I get from each crown (planted as bought one year olds five years ago), though I have noticed that some crowns do better than others - but I'm sure that between late April and mid June it is more than three or four. I'm guessing eight each from most of the 20 crowns.
The ones I planted were left alone in the summer of their first year, lightly "sampled" in their second year, lightly harvested their third year, and go berserk now.