Although appealing to more refined tastes, art as a collectible has not always performed so profitably. During 2003, Sotheby's sold the Edgar Degas bronze sculpture Petite Danseuse de Quartorze Ans at auction for a price of $10,311,500. Unfortunately for the previous owner, he had purchased it in 1999 at a price of $12,377,500. His annual rate of return on this sculpture was percent. (Do not include the percent sign (%). Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places. (e.g., 32.16))