Facebook filed for an initial public offering on Wednesdsay and included an updated report on the giant social network’s user and usage data.

The company’s total number of active monthly users, which it defines as registered Facebook users who have logged in and visited the site via Web browser or mobile device (including interactions from third-party sites), was 845m at the end of December. That’s up by about 45m since the company’s last update at September’s F8 developers conference, and a 39% increase compared to the same period last year.

The company stated that future active monthly user growth “depends on our ability to retain our current users, re-engage with inactive users, and add new users, including by extending our reach across mobile platforms”.

Of those 845m, 161m came from the US, while 46m were from India and 37m from Brazil — two areas that are key source of growth, according to Facebook. The company further broke out its user penetration by country:

— 80% of all Internet users in Chile, Turkey, and Venezuela are on Facebook

— 60% of all Internet users in the US and UK are on Facebook

— 20%-30% of all Internet users in Brazil, Germany, and India are on Facebook

— 15% of all Internet users in Japan, Russia, and South Korea are on Facebook

Unsurprisingly, there is 0% penetration in countries that restrict Facebook, like China.

When it comes to active users per day, the numbers are also quite impressive. As of end-December, an average of 483m people log on to use Facebook every day — up from 327m (or by 48%) compared to the same period in 2010.

“It looks like the overall monthly user growth is slowing, which I don’t think was much of a surprise to anyone. But one interesting titbit about growth is if you compare the daily active users to the monthly active users (year-over-year) the ratio went up. That’s a very good sign,” Forrester analyst Nate Elliott said in an interview with VentureBeat. “This is a company that’s worked really hard to innovate user experience in terms of the features offered, information presented to users and pull in the best of what’s social in other sites.”

“What you’re seeing with (the daily active user data) growth is all that hard work paying off,” Elliott said, adding that the company has plenty of potential for daily active growth in India and Brazil.

Some other impressive metrics regarding user engagement reported by Facebook include: