For 2008, U.S. retailers brought in a total of $701 million from PC games, down from the $910.7 million that retailers saw across 2007. And that 2007 total was a 6% drop from 2006, when retail PC games accounted for roughly $960.7 million.

Meanwhile, console software sales grew 26% in 2008, totaling $10.96 billion.

However, those figures don't account for digital distribution or subscriptions. Last year, NPD claimed that falling retail sales of PC games were no cause for concern, as the decline was seen as "a reflection of a shifting of distribution channels."

Shortly thereafter, NPD announced that it would soon begin tracking subscriptions. The PC Gaming Alliance later said that PC gaming was "far stronger than anyone has reported," with worldwide digital distribution sales for 2007 around $2 billion.

NPD is expected to provide more details on the 2008 PC market next week.