The Answer:

The present-day movie ratings system has not changed much since it was first announced on Nov. 1, 1968. According to the Motion Picture Association of America, more than half of the movies released since then have earned an R rating. Here is the percentage breakdown of movie ratings between 1968 and 2000:

• 55% rated R
• 24% rated PG
• 10% rated PG-13 (created in 1984)
• 8% rated G
• 3% rated NC-17 (replaced X in 1990)

See our Movies channel for more information.

—The Editors