Mumford and Sons officially had the best debut week album sales of 2012 with over 600,000 copies sold. Babel had the second biggest debut week in digital sales ever with 420,000 downloads, just falling behind Lady Gaga's Born This Way last year. The only other indie distributed album to do better was The Eagles' Long Road Out of Eden back in 2007. Another interesting fact is 1 out of every 10 Spotify users in the US streamed at least one track from Babel.
Coming in second only to Born This Way in digital sales is HUGE considering that Born This Way had the $1 Amazon promotion. It's very possible it would have been the best ever if not for that.