In an updated filing with the SEC yesterday, Facebook revealed that in December 2011, 432 million people accessed the social network from a mobile device — a 76 percent increase since December 2010. Facebook in part attributes the increase to the launch of its iPad app and its purchase of Snaptu, a company that helped Facebook deliver its mobile site to over 2,500 feature phones and other devices, in April 2011.

58 million of these 432 million people never even touch Facebook's website, a big missed opportunity in terms of ad impressions since the mobile site doesn't display ads. With new mobile news feed ads launching soon, Facebook could capitalize on the huge amounts of traffic its mobile app and mobile website receive each month. Here are three charts from the SEC filing that illustrate Facebook growth in terms of three month periods since 2009:

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While mobile usage is clearly on a roll — Nielsen's "Q3 2011" report confirmed that Facebook's mobile app gets the most monthly engagement of any app on iOS or Android — Facebook's daily user growth worldwide appears to be slowing as the social network achieves higher market saturation.

If you look closely, you'll notice that Facebook's daily active user growth is decelerating pretty quickly. For the four most recent three-month periods, daily active user growth grew at a rate of 13.8 percent between December 2010 and March 2011, then 12.1 percent, then 9.6 percent, and in the most recent three month period, just 5.69 percent. Mobile monthly users on the other hand grew less predictably at a rate of 17.55 percent between December 2010 and March 2011, then 12.85 percent for the following three months, then 15.69 percent, then 14.89 percent in the most recent three-month period.