I think this tool doesn't work particularly well.
It doesn't show any results for insurance.aes256, which was that high encrypted political doomsday file that was circulated during the wikileaks affair.
Though I don't think the key to that file was ever actually released anyway, making it completely useless.
This site illustrates the possibilities. It collects information from roughly 4%-6% of all torrent downloads all over the world. About 50% of all downloads made through private trackers serving local networks. About half of the rest are semi-private. In spite of having open registration, there are many other restrictions. So I’d say we "see" about 20% of all public tracker downloads.