According to the independent NPD Group, through July Pokémon Diamond is the best-selling video game of the year on any system, while Pokémon Pearl ranks No. 3. Pokémon Diamond and Pokémon Pearl for Nintendo DS have sold more than 3 million copies in the United States alone.

The newly released Pokémon Battle Revolution already ranks at No. 5 on the list of best-selling Wii games for the year.

Pokémon games have helped boost sales of Nintendo hardware. According to the NPD Group, Wii and Nintendo DS were again the two best-selling video game systems in the United States in July.

"These hard numbers show that the Pokémon franchise and Nintendo's systems are striking a chord with players of all ages and drawing in huge numbers of new players year after year," says George Harrison, Nintendo of America's senior vice president of marketing and corporate communications. "But anecdotally we're also seeing that these new Pokémon games are appealing to older players, the same ones who played the original Pokémon games when they debuted in the United States almost 10 years ago."