It's a lot. It seems to be well spent though, the quality of everything is so high, the 4th season felt like a movie in it's execution (pardon the pun) at times.

The CGI is fantastic, it's only when you watch a video like this do you realise half of the scene doesn't even exist, most of it so subtle you don't even think of it as CGI.

As an aside talk of TV show budgets always remind me of Star Trek: The Next Generation.

The last seasons of those over 20 years ago now in 1992 and 1993 cost something like $2m dollars an episode on average, and they made not 10, but 26 episodes in a season.

That was one hell of an expensive show.