It's the decade before the vaccination program began, which is the 70s. Even then, according to the link the death rate is not 30% or 0.3% but 0.0125% which re

It's the decade before the vaccination program began, which is the 70s. Even then, according to the link the death rate is not 30% or 0.3% but 0.0125% which really seems miniscule for such a huge program to be rolled out.