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Roku and Chromecast (S GOOG) were the two most successful streaming devices sold in the U.S. in 2013, according to new data from Parks Associates, which puts Apple (S AAPL) TV on third place.

Google sold an estimated 3.8 million Chromecast streaming sticks after introducing the product in mid-2013, according to Parks, which also estimates that this about equals Roku’s sales throughout 2013. Apple is trailing, and sold just a bit more than two million devices in the U.S. last year, according to data shared by Parks.

However, the picture looks a little different beyond U.S. borders. Globally, Apple has sold more than 20 million Apple TVs since launching the device in 2007, whereas Roku’s total sales since its launch were 8 million by the end of 2013.

One reason for this discrepancy is that Roku thus far is only available in the U.S., Canada, the U.K. and Ireland, whereas Apple is selling its Apple TV in dozens of countries. Google is quickly expanding its international reach as well: After launching just in the U.S. in 2013, Chromecast is now available in 19 countries.

Parks published data in June suggesting that Chromecast usage was down, with Chromecast owners using the device less frequently than they did six months ago. Google has since released data of its own, showing that per-minute usage of active devices continues to rise. Parks analyst John Barrett argued in response that both could be true:

“The two data sets are…not contradictory because average use among active users can be increasing even while the percentage of owners using the device is declining.”