The Motion Picture Association of America is celebrating the 50th anniversary of the film rating system by releasing historical documents related to its creation and data showing that, among other things, more than half of films with ratings are rated R.

MPAA created the voluntary ratings system in 1968 as a replacement for the Hays Code, which was a set of guidelines imposed by movie studios regulating content in films. For example, movie scenes featuring "toilet gags" and interracial relationships were at one point prohibited by the code. The ratings system gave filmmakers and studios more freedom about what they could put in films while giving audiences more information about a film's content.

The ratings system would change over the years. Most notably, the rating of PG-13 was created in 1984 following public outcry about violence in PG films, particularly "Indiana Jones and the Temple of Doom." PG-13 is now the most common rating for summer blockbusters but MPAA noted that of the nearly 30,000 films with ratings, more than 17,000 are rated R.

"Given the extraordinary changes in our culture, entertainment and society over the last 50 years, this anniversary feels particularly hard-earned and special," MPAA CEO Charles Rivkin said in a statement. "We could point to many factors behind the ratings' success, but the clearest one of all comes directly from our founding mission: to maintain the trust and confidence of American parents."

Other entertainment industry associations have created ratings systems similar to the one pioneered by MPAA. In 1985, the Recording Industry Association of America created "parental advisory" labels for music albums with explicit content. The Entertainment Software Association established a ratings board for video games in 1994.

MPAA has created a digital archive of documents related to the creation and evolution of the film ratings system. It is available at http://bit.ly/2AyVtOE

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