A recent study by retail analysis group NPD, which consisted of putting tracking software on a group of 12,500 volunteers, has found that video piracy is a lot more common than initially thought. Only 2/10 people downloading video got it from a legitimate source such as Apple, and the other 8/10 downloaded from P2P networks. The study also found that 60 percent of video files downloaded from P2P sites were pornographic, 20 percent were television shows and 5 percent were mainstream movie content. There are several good reasons behind the high amount of piracy, however. There is a much larger volume of content available on P2P networks, there are no DRM's to stop someone from converting the video to a different format and/or burning it to DVD, illegal videos are generally of higher quality, and P2P doesn't cost anything.