The 10 most successful R-rated movies ever are not what you think

20th Century Fox

Sometimes it pays to be restricted.

R-rated films limit their audiences based on excessive violence, sexual situations, drug use, and language, as determined by the MPAA.

Even so, the box office doesn't always take a hit.

"Deadpool" had the biggest R-rated opening weekend with $132.43 million, but when looking at total grosses of R-rated films adjusted for inflation, the breakout Marvel movie doesn't make the top 10. (In fact, it sits at No. 17.)

"The Matrix Reloaded," which previously held "Deadpool's" opening record, and "American Sniper" also surprisingly don't qualify, ranking at 11 and 15, respectively. "The Hangover" doesn't even make the top 20; it placed at No. 28.

Interestingly, 7 of the top 10 R-rated films are from the 1970s, and only one is from the new millenium. 

Take a look at the top 10 highest-grossing R-rated movies of all time adjusted for inflation (to keep things on an even playing field):

The ranking comes from Box Office Mojo's list of top domestic adjusted grosses of R-rated movies.

10. "Terminator 2: Judgment Day" (1991) — $417.47 million *all figures adjusted for inflation

9. "National Lampoon's Animal House" (1978) — $440.33 million

8. "M.A.S.H." (1970) — $460.61 million