The virus is asymptomatic for 2 weeks and the number of infected has a doubling time of 6 days. This gives us, roughly, death/(currentinfected/4). Or in other words multiply the 4% by 4 for the correct number.
The second main method to calculate it is death/(death+cured). Pick whichever one you prefer.
But you need accurate statistics for what is going on in the first place.
