CFR = Number of Deaths / (Number of Deaths + Number of Recovered)
According to the official numbers for Coronavirus, as of this moment, this is:
910 / (910 + 3578) = .20, or 20%
The vast majority of these cases, however are in China, where the healthcare system is overwhelmed. In a country where the healthcare system is not (yet) overwhelmed, the CFR will almost certainly be lower, as they can put many of these patients on ventilators and provide the care they need to recover.
ventilators are not on every street corner..