With 2012 nearing its end we begin our annual look at the most-pirated entertainment titles across various categories, starting today with TV-shows. Game of Thrones comes out on top this year, followed by last year's number one Dexter. Episodes of both shows are shared among millions of people, with airing delays and limited legal download options among the key reasons to pirate.

With 4,280,000 downloads for a single episode, Game of Thrones has the honor of becoming the most pirated TV-show of 2012.

Over the years the number of TV-show downloads on BitTorrent has leveled off a bit, but this year we saw a small increase again.

The majority of TV-show piracy, more than 80 percent, occurs outside the US and lacking availability is the top reason why people turn to BitTorrent.

For chart leader Game of Thrones this is no different. Airing delays and HBO’s choice not to make it widely available online are two of the top reasons why so many people pirated the show.

Game of Thrones is particularly popular in Australia, where people have to wait a week longer than fans in the U.S. to view the show. Nevertheless, even in the U.S. hundreds and thousands are downloading the show for free, although many would love to pay for it if HBO offered a standalone HBO GO subscription.

In common with many branches of the entertainment industry, the challenge for TV companies such as HBO is to come up with a business model that allows users to consume what they want at any given time, without losing existing revenue in the process.

When that puzzle is solved worldwide the number of unauthorized downloads will be pretty much insignificant.

Below we have compiled a list of the most-downloaded TV-shows (single episode) in 2012, together with the TV audience in the U.S. The data for the top 10 is collected by TorrentFreak from several sources, including reports from all public BitTorrent trackers.