Of 1,638 video games passed by North America's Entertainment Software Rating Board in 2010, 55 percent (901) were given an "Everyone" rating, reflecting their suitability for those aged 6 and upward, while 5 percent (82) were labeled "Mature 17+."

Twenty-one percent (344) were rated Teen; 18 percent (295) were placed in the Everyone 10+ category, and 1 percent (16) were intended for younger children of 3 years old and up.

That's in contrast to the best-selling games of the year. Retail data from NPD shows that games with Mature ratings are among the year's biggest blockbusters.

Call of Duty: Black Ops, rated Mature, was 2010's top performer in the USA, following a November 2010 launch. The title went on to shift 13.7 million units by the end of February 2011.

Sports game Madden NFL 11 (rated Everyone) came second in the annual rundown, sci-fi shooter Halo: Reach (Mature) was third, traditional Nintendo platformer New Super Mario Bros. Wii (Everyone) was fourth, with wild west tale Red Dead Redemption (Mature) in fifth.

In 2009, 60 percent of the 1,075 games rated by the ESRB were judged fit for the Everyone tag, 18 percent were Teen, 16 percent were Everyone 10+, and 6 percent were stamped Mature.