I've no idea, but in central California I often see at least one person wearing them any time I go near a busy beach, which is most weekends. If the article below is to be believed, approx 60,000 pairs in Q1. Given the enormous disparity in price between the two I'd assume they are outselling Glass as well.

http://www.businessinsider.com/snap-took-in-8-million-from-t...