From the CNN exit polls. Most voter decided a long time ago (no surprise here).

[Silent3]

3. I made up my mind about 35 years ago

I suppose early in my post-18 y/o life, I might have briefly considered the idea that someday in the then-unknown future, a decent Republican might come along with moderate positions and better character than some especially unappealing Democrat.

I was quickly disabused, however, of the notion that any decent Republicans would ever come along, at least on the national ticket.