From the Guardian -
What is the mortality rate of the new coronavirus?
It is probably about or a bit less than 1%. Much higher figures have been flying about, but the chief medical officer, Chris Whitty, is one of those who believes it will prove to be 1% or lower. The World Health Organization’s director general, Dr Tedros Adhanom Ghebreyesus, talked of 3.4%, but his figure was calculated by dividing the number of deaths by the number of officially confirmed cases. We know there are many more mild cases that do not get to hospital and are not being counted, which would bring the mortality rate significantly down.