Pokémon, the fastest-selling video game in the world (What, you thought Mario was the best-selling video game in the world? You are right! We'll get to that later.), will become the #1 all-time best-selling video game franchise in the world sometime in 2011 or 2012. I used calculations that were rounded to increase Mario's sales and decrease Pokémon's sales. Here are the statistics.
Mario: 200 million copies sold from 1982 to 2007 inclusive (I rounded the years to make Mario seem faster and Pokémon pokier... er, slower).
Pokémon: 175 million copies sold from 1996 to 2008 inclusive.
Mario: 7.7 million copies per year (about one game every 4 seconds; this stat was not used but it is interesting)
Pokémon: 13.4 million copies per year (about one game every 2 1/2 seconds)
Year Mario Pokémon Difference (millions, end of year predicted)
2007 200.0 175.0 25.0 Mario
2008 207.7 188.4 19.3 Mario
2009 215.4 201.8 13.6 Mario
2010 223.1 215.2 7.9 Mario
2011 230.8 228.6 2.2 Mario
2012 238.5 242.0 3.5 Pokémon
More realistic estimates show that the Pokémon 15th Anniversary Year of Celebration will end with Pokémon claiming its spot as #1 game franchise of all time, a spot it will keep for years to come. Of course, Nintendo won't care, except for all the publicity it will recieve, because they are just beating themselves.
Because video game sales rarely follow a straight line, Pokémon will probably beat Mario when Generation V comes out.