I haven’t seen the definition of “recovered” but am assuming it means “admitted to hospital, and survived”.
A lot will depend on how bad a case you need to have before they will admit you, particularly in an overstressed medical system.
Anyway, the real, accurate, denominator must be “number who have been infected, even if they only develop mild symptoms”. We currently have no way to determine this number. We can only guess.
I’m guessing it scales with the number seeking medical attention.
I’ve seen estimates all over the map.
A lot of the confirmed mild cases are being sent home and told rest, fluids, Tylenol, and call us if you start having trouble breathing. Most seem to recover just fine, but I wonder how many are counted as recoveries.
The official numbers give a worst case maximum fatality rate.
I bet history will record half that rate. As to how may died in China or Iran, we’ll never know. Not my problem...