Sum of the Arts

Percentage of 40,000 museum visitors surveyed in 2010 who enjoyed guided tours = 31

John Singer Sargent's unfinished portrait of Italian actress Eleonora Duse (1893), oil on canvas (Herta and Paul Amir Collection, via Wikimedia)
John Singer Sargent’s unfinished portrait of Italian actress Eleonora Duse (1893), oil on canvas (Herta and Paul Amir Collection, via Wikimedia)

Inspired by the Harper’s Index, Sum of the Arts is a periodic tabulation of numbers floating around the art world and beyond.