It would make more sense to refer to voting outcomes as they really are.
85 Mio. people live in Germany. Of those, roughly 60 Million are allowed to vote, so around 70%. Of those 70%/60Mio., 80% voted, that is 48 Mio. or 55% (a little more).
28,5% of those voted for the CDU - but in the media, it is usually displayed as if 28,5% of Germans voted for them. But doing the math, it's only 13,5 Mio., or 16% of the population.
So, the truth would be: 16% of Germany's population voted for the CDU, which now is the strongest party in the German parliament. That's a big difference from 28,5%.