Following market research firm The NPD Group's release of January's sales figures, Nintendo of America boasted that its own growth rate is outpacing the industry as a whole. With 20 out of the month's top 30 games on its platform, Nintendo says its year-over-year sales for the month grew by $300 million, while the rest of the industry grew $150 million -- the company claims its success is "offsetting declines" on other platforms. "Nintendo’s significant contribution to January’s industry growth validates our internal research showing that Nintendo continues to expand the gaming audience," says Nintendo of America's EVP of Sales and Marketing Cammie Dunaway. The company also said its 680,000 Wii hardware units sold represent a 148 percent increase over January 2008. More than 18 million units have been sold in the United States, since Wii's debut in November 2006. The Nintendo system was the top-selling console for the month, and was accompanied by three first-party games topping the NPD's 10 best-selling software chart -- Wii Fit (over 770,000 sold), Wii Play (nearly 415,000), and Mario Kart Wii (over 292,000). "We are excited to see that consumers, new and existing, are choosing to entertain themselves in new ways with the diversity of our software lineup," Dunaway says. Nintendo DS was the second top-selling system in January, moving over 510,000 units, up 99 percent over the same period in the previous year. The system has so far sold over 28 million units in the U.S. since the handheld launched in November 2004. The portable was also accompanied by two DS titles in the month's 10 best-selling software chart, New Super Mario Bros. at the seventh spot with almost 135,000 copies sold, and Mario Kart DS at number eight with over 132,000 sales, a remarkable achievement considering the two were released in May 2006 and November 2005 respectively.