As if you didn't know

“The world of contemporary art is not that big. There are about 10,000 museums, art institutions and public collections worldwide, 1,500 auction houses and about 250 annual art fairs and shows. There are 17,000 commercial galleries worldwide, 70 percent of which are in North America and Western Europe. Average turnover per gallery is about $650,000, implying gross sales for the primary market and part of the secondary market of about $11 billion – of which $7 billion could be considered contemporary art.”
Don Thompson in his book The $12 Million Stuffed Shark: The Curious Economics of Art and Auction Houses