I would not bet on over 50% of Trump's supporters having done that, because he did well enough with 40-50-somethings who'd be too young to vote in 1984 (to have voted in 1984, you'd need to be a minimum of 50, and to vote in 1980, you'd have needed to be a minimum of 54) and it's not like a bunch of teens/early-20s were Reagan's strongest demo, either. In 2016, you wouldn't find all that many Reagan voters left who were under 60, and that's not going to be a majority of anyone's support.
Nope. The median age of a Trump voter in 2016 was just over 50 years old (born 1966), and like the Mikado posted above older Gen X'ers weren't really that large a part of the electorate in 1980/84.
What if we only look at Trump voters who could vote in 1980 and/or 1984?
