Videogame retailers as a whole have shown vast improvement in their efforts to restrict sales of mature-rated games to minors, according to a recent study by the Federal Trade Commission.

The FTC sent undercover shoppers to specialty retailers, discount stores and electronics stores to test clerks' adherence to Entertainment Software Ratings Board restrictions on the sale of M-rated games to consumers under the age of 17. According to the results of the test, 20 percent of mystery shoppers aged 13-16 were able to buy M-rated games. That's down from 42 percent in 2006 and from 82 percent in 2000 when the study was first launched.

"Video game retailers have clearly stepped up their efforts to enforce their store policies, and they deserve recognition for these outstanding results," said ESRB president Patricia Vance in a statement. "We commend and applaud retailers for their strong support of the ESRB ratings, and will continue working with them to help ensure that these levels of compliance are sustained if not further increased."

According to the FTC, sales of videogames to minors were far less frequent than sales of mature-rated DVDs, CDs labeled as explicit and tickets to R-rated movies. Discount and electronics stores often had varying responses to underage requests to buy different media. Best Buy, for example, rejected 80% of underage buyers of video games but turned away underage shoppers for PAL (parental advisory label) music only 47% of the time, R-rated movie DVDs only 38% of the time, and unrated movie DVDs only 17% of the time.

The FTC found that, of all the retailers it tested, GameStop performed best, turning away 94% of underage videogame shoppers trying to buy M-rated games.