I was able to find a study that says
42% of the The Force Awakens audience was repeat viewings, but I think we can assume that that was at the higher end and likely does not reflect TLJ numbers, which could be something like 30%ish.
Also, I would add, one of the few movies I've seen in theatres twice, Avengers Age of Ultron,
is a film I now consider to be bad and I never really cared for it. I operate in different social circles, so I saw it with different people though I seem to recall a lot of reviewers who didn't like the TLJ going to see the movie again to give it another chance. So even seeing a film twice isn't necessarily am indicator they like it.