Although appealing to more refined tastes, art as a collectible has not always performed so profitably. Assume that in $2015,$ an auction house sold a statute at auction for a price of $$10,458,500.$ Unfortunately for the previous owner, he had purchased it in $2010$ at a price of $$12,510,500.$ What was his annual rate of return on this sculpture?Note: A negative answer should be indicated by a minus sign. Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$