Fig. 2

Bubble plot representation of the 30th of April Case Fatality Rate (a) and of the 30th of April Normalized Case Fatality Rate of USA (in light blue), Italy (in red), of UK (black line), France (in magenta), Spain (in green), Sweden (in yellow) and Germany (in cyan). In a, the CFRs are distributed within a large range of values, whereas in b the normalized CFRs values are clustered in three well-distinct groups: Germany forms the first group, Italy, Spain and USA the second group and, finally, Sweden, UK and France the third group with the higher normalized CFR value