I suspect you are lumping two separate things together. Infection rates and mortality rates are not the same thing.
Nothing has been said in any source I have seen about infection rates. Could be high, could just as easily be low.
Mortality rates are not the same thing. They refer to the number of people who die, once they get it in the first place.
The mortality rate thus far is impossible to calculate because no one has gotten better. Based on the condition of the people who are sick, and the known fact that it does not respond to any known treatment, it looks like it will be high.
And yes, I do understand statistics. I even taught it for a year at the University of Washington. Based on your comment, I suspect you are suggesting multiplying the infection rate times the mortality rate to get the overall outcome to expect within the population as a whole. This may or may not work. The problem comes when you have multiple exposure opportunities. If enough people are sick, then the relevant number will be how many people are naturally resistant, not how many people will get sick from a single exposure opportunity.