A new report from research firm SuperData claims that Blizzard's juggernaut card game Hearthstone is bringing in $20 million a month - more than any other card game, and placing it ahead of DOTA 2.

An interesting stat for mobile players: SuperData says that Hearthstone has a bigger audience on mobile, where 9 million people play on iOS and Android, than on PC, where 8 million players hang out.

The card game's huge new expansion, The Grand Tournament, is out this month.