The blood-soaked medieval drama "Game of Thrones" was the most pirated U.S. television series of 2013, EW.com reported. Coming in at No. 2 on the list of shows most frequently illegally downloaded is "Breaking Bad," followed by "The Walking Dead" at No. 3, "The Big Bang Theory" at No. 4 and "Dexter" at No. 5. Rounding out the top tier are "How I Met Your Mother" at No. 6, "Suits" at No. 7, "Homeland" at No. 8, "Vikings" at No. 9 and "Arrow" at No. 10.