With active users surpassing the 25 million mark and a 205% jump in year over year unit sales, 2009 was an extremely good year for Valve's Steam service.

Valve announced Steam's spectacular 2009 today, providing plenty of statistics to back it up. Active accounts are up 25% to more than 25 million, with 10 million of those maintaining Steam Community profiles. The service now hosts more than 1,000 games from more than 100 developers, which was a key factor in the 205% rise in unit sales, which makes for the fifth year in a row that the figure has jumped by more than 100%.

"Steam turned five years old in March 2009," said Gabe Newell, president of Valve. "With the introduction of each new platform feature released over the years — such as the Steam Community, Steam Cloud, and Steamworks — we've seen corresponding growth in account numbers, concurrent player numbers and developer support for the platform. As such, we plan to continue to expand and grow the platform to better serve the developers supporting the open platform and millions of gamers logging in each day."

In fact, the service surpassed a peak number 2.5 million concurrent users in December, no doubt aided by the releases of Modern Warfare 2 and Left 4 Dead 2. The increased number of users also helped push Steam's monthly average player minutes past 13 billion.

With more and more PC players turning to digital distribution for their gaming fix every year, I'd expect Steam to continue gathering steam in 2010.