Interesting. The graphs on that website do not agree with the ones on Wikipedia. For example, for coal in 2016 Wikipedia says ~220 TWh but Strom says ~135 TWh.
EDIT: I see my mistake. I did not add both brown (~135 TWh) and black coal (~100 TWh) together (surprised to see those broken out, but it's a valid difference). In that case, the numbers still do not agree, but at least they are comparable.
Share of electricity production in Germany in 2019:
Coal 19.5% + 9.5%
Gas 10.5%
19.8 + 9.5 + 10.5 = 39.8%