I'm sure it wasn't scaled or normalized at all. It's global annual deaths.
It would be interesting to see what percentage of annual premature deaths they account for in countries with any deaths.
Ie lions and hippos are presumably a much large percentage of annual premature deaths in countries where there are any lion and hippo deaths, whereas mosquito deaths happen in many more countries, and homicides in basically all countries.
I'm actually quite shocked by the number of lion and hippo deaths.