Although appealing to more refined tastes, art as a collectible has not always performed so profitably. During $2003,$ Sotheby$$s sold the Edgar Degas bronze sculpture Petite Danseuse de Quatorze Ans at auction for a price of $$9\mathrm{.}88$ million. Unfortunately for the previous owner, he had purchased it in $1999$ at a price of $$13\mathrm{.}31$ million.

What was his annual rate of return on this sculpture?