They include a breakdown by date of onset as well, which isn’t exactly the method you suggest (but I read somewhere that recovery time is ~2 weeks for mild case

They include a breakdown by date of onset as well, which isn’t exactly the method you suggest (but I read somewhere that recovery time is ~2 weeks for mild cases and ~3-6 weeks for severe). Case fatality by date of onset: [<Dec 31] 14.4% (n=105) [Jan 1-10] 15.6% (n=653) [Jan 11-20] 5.7% (n=5417) [Jan 21-31] 1.9% (n=26468) [>Feb 1] 0.8% (n=12030) That does make the overall fatality rate look quite a bit worse than the naive calculation.