NEW YORK — U.S. video game retail sales dropped 13 percent in January, another down month for the industry after a difficult 2009.

In all, Americans spent nearly $1.2 billion on video game systems, software and accessories during the month, market researcher NPD Group said Thursday.

Software sales fell 12 percent from the same month a year earlier, to $597.9 million.

January does not tend to be a big month for video games, which sell heavily during the holidays, though it is when many people trade in the gift cards they got for Christmas.

The month's best-selling title was Nintendo's "New Super Mario Bros.," followed by "Mass Effect 2" from Electronic Arts, which launched Jan. 26. Other games such as Activision Blizzard's "Call of Duty: Modern Warfare 2" and Nintendo's "Wii Fit Plus" also did well.

January hardware sales tumbled 21 percent from a year earlier to $353.7 million. In December, hardware sales hit nearly $2.2 billion and were up from a year earlier.

NPD said Thursday the Wii kept its spot as the month's best selling console with 465,800 units sold, followed by the hand-held DS with 422,200. Microsoft's Xbox 360 was in third place with 332,800 units, tailed by Sony's PlayStation 3 with 276,900.

Sales of accessories climbed 2 percent to $217 million.