It's not as simple as that. First of all, why pick only 2018, but not 2019, or in fact an average of previous years? Second problem is that 2020 was an exceptio

It's not as simple as that. First of all, why pick only 2018, but not 2019, or in fact an average of previous years? Second problem is that 2020 was an exceptional year. People contacted each other less, so we expect them to die less from many other causes (traffic accidents, other transmissible diseases, etc).