How much revenue did you generate for Facebook last year? That depends on where you live.

Facebook announced on Jan. 27 that its revenue reached almost $18 billion last year, representing more than 40% growth over 2014. It also made almost $4 billion in profit last year, as its user base grew to 1.6 billion monthly active users.

Worldwide, the average Facebook user generated almost $12 in revenue for the company last year—mostly from advertising. But it was dramatically higher in the US and Canada, where the ad market is most lucrative, than other regions.

Overall, Facebook’s average revenue per user continues to grow. It almost doubled from 2013 to 2015 as the company continued to get better at generating ad revenue on mobile devices.

The company is mostly getting better at generating revenue in its richest markets, though. In 2015, Facebook made almost $13 more per user in the US and Canada than it did in 2014. But it only extracted another $0.51 per user—about 15%—in the non-Europe, non-Asia-Pacific “Rest of World” region. That’s slower growth than the year before.

We calculated Facebook’s annual average revenue per user by adding up its published quarterly figures over the course of the year. This isn’t a perfect methodology, but it’s the one Facebook uses in its annual reports filed with the US Securities and Exchange Commission.