According the Minecraft’s Official Site, the game has now sold over 22 million copies on Mac and PC alone with 13,000 coming within the past 24 hours. This number is up from the 20 million that was reported back in June. Some are considering this increase to be due to the recent holiday season as well as the release of Minecraft: Story Mode.
It is not known how many copies have been sold across all platforms. We do know that the number was 54 million in June 2014.