Game of Thrones keeps getting bigger and bigger.

According to internal numbers, HBO's flagship series is averaging 23.3 million viewers per episode in Season 6, including first air, repeats, DVR and streaming, USA Today reports. That's up 15 percent over Seaason 5, the series' previous highest-rated season.

Sunday night premiere ratings are up 6 percent to 7.3 million viewers an episode. Overall TV and on-demand viewership is up 4 percent. But the big story is that streaming viewership on the HBO Go and HBO Now digital platforms is up a whopping 70 percent over last season, with 2.5 million streams an episode.

HBO Go is available to HBO cable subscribers, while HBO Now is a standalone digital service that launched before Game of Thrones' Season 5 premiere.

Kit Harington, <em>Game of Thrones</em>Kit Harington, Game of Thrones

Game of Thrones' closest competitor, The Walking Dead, averaged 19.4 million viewers in live+7 Nielsen ratings for its Season 6 finale. It's not a perfect comparison, since HBO's numbers measure total views while AMC's are only measuring TV and DVR the first week after the premiere, so it's hard to say which is more popular.

But it's safe to say that Game of Thrones is huge.