I believe they might have used the same stuff the Washington Post used[1]. The post quoted a lower ( 7 million ) but still unreal figure in another paywall related article [2].

[1] http://www.eidosmedia.com/EN/Page/Uuid/83c5a8b2-ae9f-11de-9d...

[2] http://www.washingtonpost.com/opinions/behind-the-posts-rede...