You could compare gross across all the movies.
Here's a handy cheat sheet.
Interestingly, the domestic audience was
larger as a proportion of overall audience for
Trek XI compared with any of the TNG movies and of course made a lot more money as well. So the news there isn't that
Star Trek has gained an international following so much as it's re-building a domestic audience. I'm sure if you adjusted for inflation, the older TOS movies are right in line with
Trek XI's box office.
One topic for your students to ponder: why doesn't
Trek XI have the standard domestic/international box office split of the Hollywood blockbuster type movie, which usually hits 50/50?
Captain America was 48%/52% domestic/foreign compared with Trek XI's 67%/33%.
You'd think
Star Trek's "internationalist" philosophy would have more foreign appeal compared with all-American Cap - but is it actually off-putting? Is it just the notion that
Star Trek has a ton of complicated backstory that foreign audiences may not be familiar with? Or maybe it had nothing to do with the content - did someone blow the marketing overseas? Or was the domestic marketing just so insanely great, it resulted in unusually high domestic box office?
Box Office Mojo also has country-by-country totals so the students can dig down into the numbers and see if there were particular markets where
Star Trek did not do as well (as a proportion of the total) as summer blockbusters generally should.