a billion-dollar merchandising industry. The title family and supporting characters appear on everything from T-shirts to posters. The Simpsons has been used as a theme for special editions of well-known board games, including Clue, Scrabble, Monopoly, Operation, and The Game of Life, as well as the trivia games What Would Homer Do? and Simpsons Jeopardy!. Several card games such as trump cards and The Simpsons Trading Card Game have also been released. Many official or unofficial Simpsons books such as episode guides have been published. Many episodes of the show have been released on DVD and VHS over the years. When the first season DVD was released in 2001, it quickly became the best-selling television DVD in history, although it was later overtaken by the first season of Chappelle's Show. In particular, seasons one through seventeen were released on DVD for 13 years between September 2001 to December 2014 in the U.S./Canada (Region 1), Europe (Region 2), and Australia/New Zealand/Latin America (Region 4). However, on April 8, 2015, Al Jean announced that the Season 17 DVD would be the last one ever produced, leaving the collection from Seasons 1 to 17, Season 20 (released out of order in 2010), with Seasons 18, 19, and 21 onwards unreleased. Jean also stated that the deleted scenes and commentaries would try to be released to the Simpsons World app, and that they were pushing for Simpsons World to be expanded outside of the U.S. Two years later, however, on July 22, 2017, it was announced that Season 18 would be released on December 5, 2017, on DVD. Another two years later, on July 20, 2019, it was announced that Season 19 would be released on December 3, 2019, on DVD. In 2003, about 500 companies around the world were licensed to use Simpsons characters in their advertising. As a promotion for The Simpsons Movie, twelve 7-Eleven stores were transformed into Kwik-E-Marts and sold The Simpsons related products. These included "Buzz Cola", "Krusty-O" cereal, pink doughnuts with sprinkles, and "Squishees". In 2008, consumers around the world spent $750 million on merchandise related to The Simpsons, with half of the amount originating from the United States. By 2009, 20th Century Fox had greatly increased merchandising efforts. On April 9, 2009, the United States Postal Service unveiled a series of five 44-cent stamps featuring Homer, Marge, Bart, Lisa and Maggie, to commemorate the show's twentieth anniversary.