Islamic State’s coordinated assault in Paris last week has brought even more attention to the terror group’s frighteningly rapid global growth, and where around the world it has found traction — not just in terms of territory gained, but in support.

A study out of the Brookings Institution used Twitter to shine some light on this, comparing the countries where tweets from ISIS supporters originate. The study dealt with a sample size of 20,000 and found that Saudi Arabia is the top location claimed by Twitter users supporting ISIS in 2015. Syria follows, Iraq rounds off the top three and the U.S. takes fourth place.