It's the oldest movie they've ever covered since they started doing the box office game, so it was the first time Box Office Mojo didn't have a weekend chart. Demme will be interesting, because he has six movies that predate BOM's weekend charts. I'd recommend an investment in this: https://www.amazon.com/Weekly-Box-Office-Charts-1970s-ebook/dp/B071GPPSGR
They skipped the box office game, but for those curious, here's the Top 5 for the week of December 12th, 1979 when Star Trek: The Motion Picture came out:
1) Star Trek: The Motion Picture
2) 10
3) Apocalypse Now
4) And Justice For All
5) Starting Over
You can get ebooks with weekly top 10s going back to the 1920s!. They do not include weekly $ numbers, but there's a different book that does have totals for every movie that made some minimal amount of money