According to the NPD Group, a consumer and retail information company, for every legally downloaded video file, there are five illegally downloaded ones on P2P networks and BitTorrent sites.

The research carried out by the group shows that 8 percent of all U.S. households (6 million) illegally downloaded at least 1 copyrighted video from a P2P network in the past 3 months, whereas only 2 percent of U.S. households purchased a video legally.

Legal video downloads took place largely on Apple’s iTunes Store with 9 in 10 downloads occurring on that site, followed by Vongo (5 percent), Movielink (3 percent) and less than 1 percent for CinemaNow.

It’s hardly surprising that almost 60 percent of all illegally downloaded video files were “adult-oriented”. TV shows were the second most popular at 20 percent, and only 5 percent were “mainstream movie content”. With regards to legal video downloads, sixty-two percent were TV shows, 24 percent were music videos and 6 percent were movies.

Russ Crupnick, the vice president of the NDP Group wants the movie industry to take the issue of illegal video downloads seriously, even though only a fraction of the video downloads were feature films, and the percentage of legal movie downloads was higher than that of illegal ones. “Even though right now the majority of downloaded video content is adult-film content, the amount of intellectual property stolen from mainstream movie studios, networks, and record labels will continue to rise, unless strong and sustained action is taken to prevent piracy,” he says.