The NPD Group has released sales figures for 2005, estimating that the US spent $1.4 billion on games last year. An interesting and growing proportion of that income was from online games -- $344 million, about one quarter of the total spending, came from recurring subscription fees.

Breaking that down, NPD estimates about 85% of that recurring income is from specific games like World of Warcraft, whereas the rest -- a non-trivial $52 million -- comes from casual games portals. It's clear from the tremendous amount of money being generated by both games and gaming portals, as well as the popularity of MMOs and casual games, that online is a key area to watch in future.

While digital downloads are only a small part of the picture -- 3% of total market sales -- the area should grow, partly driven by the convenience of buying and delivering online. Of course, paying for a game through monthly subscriptions rather than a one-off box fee is appealing, though players of games like World of Warcraft don't seem to mind doing both.

This article was originally published on Joystiq.