Independent research company NPD Group has released its US video game sales numbers for May 2009.

The best selling game for the month was THQ’s new release, UFC Undisputed 2009 for Xbox 360 (the PS3 release came in fourth).

Six Wii games made the chart followed closely by the Xbox 360 and DS with five games each. Only three PS3 games made the list, although two were in the top five, and not a single PSP, PS2 or PC/Mac game made the Top 20.

The oldest game on the chart for the month is Mario Kart DS release in November 2005 coming in at number 12, down from eighth place in April 2009. Eight games released in May 2009 made the list.

The Wii has been pretty invincible around the globe since it first became available, and its sporadic failure to top sales charts in any part of the world makes news. It becomes an even more significant defeat if it comes on Nintendo’s home turf in Japan, and this is exactly what happened. The Wii lost more »