I'm really surprised by this as well. From what I can tell, the estimate that was named is "above 2.5%". This could be simply by calculating how many people die

I'm really surprised by this as well. From what I can tell, the estimate that was named is "above 2.5%". This could be simply by calculating how many people died compared to total population in the world. If 2.5% of total world population died, assuming everyone was infected, it is at least 2.5% case fatality rate and depending on how many people were not infected case fatality rate will go down.