World of Warcraft launched in China in June 2005.[30] By the end of 2007, World of Warcraft was considered a global phenomenon, having reached over 9 million subscribers[29] and exceeded US$1 billion in revenue since its release.[31] In April 2008, World of Warcraft was estimated to hold 62 percent of the MMORPG subscription market.[32] Blizzard's staff quadrupled from around 400 employees in 2004 to 1600 by 2006 to provide more resources to the game and its various expansions,[31] and Blizzard moved their headquarters to 16215 Alton Parkway in Irvine, California in 2007 to support the additional staff.