Oh, this is just people that are registered as republicans. Arguably a better metric of actual supporters, rather than just plain votes, as those include a lot of strategic votes from people that don't really like either, but just settle for whatever they think of as the lesser evil. But even using registered people is a bit iffy, because not all necessarily need to like the given candidate, just food for thought.

And since ya asked, here's the same math with votes. The 2020 election final round turnout was 66.6% and 46.8% voted Trump, that means 31.1%. And for Biden, 51.3%, so that would be 34.1%. I'm using Wikipedia's numbers btw.