Calculating rate of return:

Although appealing to more refined tastes, art as a collectible has not always performed so profitably.During 2003, sothebys sold the Edgar Degas Bronze Sculpture Petite Danseuse de Quatorze Ans at suction 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. What was his annual rate of return of this sculpture?

Please explain and answer.