There are essentially two kinds of mustard oil. The Expressed Mustard Oil, most commonly used as a cooking oil in India, is not approved for food use in the United States. It is covered under the FDA Import Alert 26-04, dated 11/18/2016. Their comments about both types of Mustard Oil are below, in quotation marks.
"Reason for Alert:"
"Expressed mustard oil ...
Take a look at this live map of the virus. The calculation is based on the number of deaths, divided by the number of confirmed cases (multiplied by 100 to get it as a percent%).
As of February 3rd 2020, that would be 362 / 17405 * 100 ~= 2.08% fatality rate.