As part of a corporate strategy meeting, Square Enix yesterday revealed the lifetime, worldwide sales figures for three of their biggest franchises.
And no, they don't mean The World Ends With You. The three biggest (at least in terms of units sold) are Final Fantasy, Dragon Quest and Kingdom Hearts, and when you combine every game ever released in those franchises, you get the following (lifted straight from the presentation):
So, yes, if you ever find yourself wondering to the night sky why Square Enix insist on milking these franchises - particularly Final Fantasy - to within an inch of their lives, that's why.
As for the Dragon Quest numbers, we'd say in some ways they're even more impressive, given the series' limited popularity in the West.