FORTUNE — By the year 2017, fewer than 20% of all Twitter TWTR users will come from North America, according to a study released today.

Currently, 29.1% of all Twitter users come from the Asia-Pacific region, the new data from eMarketer notes. That is the highest percentage of any region, and it doesn’t even include Chinese users due to the Chinese government’s ban on the micro-blogging site. By 2018, Asia-Pacific Twitter users will be 41% of all tweeters, the survey predicts.

In the U.S., Twitter seems to be approaching a plateau in terms of user growth. By 2015, total growth is projected to be less than 10%. eMarketer’s report notes that this could result in increased ad revenue growth in emerging markets, including Indonesia and India, both of which are expected to see Twitter use grow by double digits through 2018, according to eMarketer.