Yeah, in the 2011 Master Development Plan, the average cited for the previous 10 years was 985,000. However, the yearly numbers had actually been decreasing since 2005-06 (hello Epic pass). I haven't seen other numbers, but I imagine that trend has stopped or at least slowed.
Last season, VR reported 5.5 million visits for its four resorts. Seems I've read that Vail and Breck both get about 1.6 million and Keystone 1 million, which leaves Beaver Creek with about 800K.