The best representation is Diamond Princess, Cruise Ship. Everyone was tested. So they know the true infection rate, the true death rate and true recovery rate. Cruise ships are packed with a bunch of old farts, so take the death rate from Diamond Princess and divided it by two. The complete set of numbers are not in, but it is going to come in at about .6% to .7%.
If you compare to the flu, over 65 year olds represent 80% of the mortality rate of the flu, so maybe divide by 4 or 5.