Not a medic, so just curious. It is reported that "most" patients will experience C-19 as mild cold symptoms. In this case, it seems likely that many infected individuals will pass undetected, perhaps even unaware themselves that they have had anything more than a dose of the sniffles. They won't seek testing, and therefore won't be reflected in the statistics. But those who develop serious symptoms - and die - will be 100% accounted for in the statistics. So it is likely on this basis that the mortality rate expressed as a percentage is overstated.