Wrong. They are currently using known infected divided by dead to arrive at death rate. In fact unless they test everyone in America (won't happen) they will have no accurate way of determining how many are infected which is needed to determine the accurate kill rate.
“In fact unless they test everyone in America (won’t happen) they will have no accurate way of determining how many are infected which is needed to determine the accurate kill rate.”
Due to (very likely) deliberate under-reporting of fatality count (China, et al), as well as those who die without the cause of death being accurately diagnosed, there’s also no way of knowing the actual number of corona-related fatalities - which is also necessary to determine the actual kill rate.