In EA's third fiscal quarter financial reports, it was announced that Battlefield 3 Premium hit 2.9 million subscribers by December 31 of this past year (up from July's total of 1.3 million). For a rough estimate, just multiply 2.9 million by $50. Yeah, that's a lot of cash. For the third quarter specifically, EA says Premium generated $108 million.
Of course, I would only assume that these numbers reflect subscriptions also obtained through the Battlefield 3: Premium Edition, which was $30 at pretty much any retailer during Black Friday. Seems like there'd be some lost cash there, but hey, $108 million alone just for a stream of still being released digital content isn't half-bad.