The Friday File: Since 2006, ten artists have turned over $1 billion at auction. Top of the list: Pablo Picasso at $3.43 billion, followed by Andy Warhol at $3.38 billion, Zhang Daqian at $2.03 billion, Qi Baishi at $1.91 billion and Francis Bacon at $1.56 billion. The best performing genre since 2006, 20^th-century Belgian painting, up a whopping 1,148% thanks in large measure to Rene Magritte. Eat your waffles!