summotorrent used to have an rss feed which was an agreator of all the different tracker out there.
he basically subscribed to the feed, downloaded everything and recorded the downloads from the tracker published stats.
someone did a similar study using mininova feeds, but that not considered as accurate because mininova blocks porn, which skews the numbers.
MPAA did a study using isohunts numbers and they came to 54%.
This was the lowest percentage that i could find amoung all the studies.
as for you top 100 two points you need to make you are looking at the pirate bay and ignoring sites like eztv.it/tvtorrents.com etc which obviously skews the results.
second you are looking at a torrent by torrent distribution and not a content by content distritution
what i mean by that you are not summing all torrents of the same content together
http://www.mininova.org/search/?search=heroes+s03e13
see how their are multiple different versions of the same show.
lol upload of this episode of heroes is listed 5 times before the fold.
The stats i am giving you come form the summing of all those pages of heroes episode torrents.
lastly look at your list a single episode of heroes is in the top 100 for this week.
AXXO current release is at the top. Heroes will show up in the top 100 every week it airs, AXXO spikes when he releases a new video (because people subscribe to his feed).
Something that shows up consistantly in the top 100 week after week, across multiple submitters is going to over all be much larger number then you can get from a short time spike cause by being a famous submitter (pirate) submitting a new movie this week.