You have the following historical annual total returns on Terlingua Oil & Gas Exploration: Year Annual total return (%) 4% 5% 17% 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2% 15% 9% 15% 3% 6% 3% Calculate the sample standard deviation of annual return. Do not round at intermediate steps in your calculation. Express your answer in percent. Round to two decimal places. Do not type the % symbol