Of the 10 million subscribers for this game, only 4.5 million are in NA/EU which pay a regular monthly fee and will very likely to be playing from home using a physical copy they purchased. The other 5.5 million users in Asia do not need to own a physical copy of the game to play and majority will be playing in PC bang/internet cafe so assuming subscribers is equivalent to copies of the game sold is an unsafe assumption in my opinion.
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