My most common use of torrents is not piracy.
"...89.9 per cent of them were illegal and, of the remainder, 8.2 per cent was porn."[2]
"Overall, about one percent of the total files were categorized as "likely noninfringing."[1]
[1] http://arstechnica.com/business/2010/01/bittorrent-census-ab... [2] http://arstechnica.com/tech-policy/2010/07/only-03-of-files-...