Six of the ten games are Nintendo titles.
http://www.nintendoworldreport.com/news/24411
In honor of their ten-year anniversary, Amazon Japan has released their list of the top ten best-selling games of the decade, starting from October 1, 2001 and ending on June 30, 2010.
Out of the top ten titles, six of them are Nintendo titles. In first place is Dragon Quest IX: Sentinels of the Starry Skies for the DS. The title was released in Japan in 2009 and has become one of the best selling titles in the country. At number three is New Super Mario Bros. Wii. In fourth place is Wii Fit, released in 2007. In fifth place is Tomodachi Collection for the DS. Also known as Friend Connection, the title has players creating Mii characters and interacting with them in a virtual world.
In eighth place is New Super Mario Bros. for the DS, released in 2006. The final Nintendo title in the list is Animal Crossing: Wild World for the DS, originally released in 2005. The title is the second oldest game in the list, with the oldest being Dragon Quest VIII, released for the PlayStation 2 in 2004.
Four of the titles belong to Square Enix, with two being Final Fantasy titles (Final Fantasy XIII and Final Fantasy XII), and two being Dragon Quest titles (Dragon Quest XI and Dragon Quest VIII).
The full list is as follows:
1. Dragon Quest XI: Sentinels of the Starry Skies (DS)
2. Final Fantasy XIII (PS3, Xbox 360)
3. New Super Mario Bros. Wii (Wii)
4. Wii Fit (w/ Balance Board) (Wii)
5. Tomodachi Collection (DS)
6. Monster Hunter Freedom Unite (PSP)
7. Dragon Quest VIII: Journey of the Cursed King (PS2)
8. New Super Mario Bros. (DS)
9. Animal Crossing: Wild World (DS)
10. Final Fantasy XII (PS2)