Using the data in the following table, and the fact that the correlation of A and B is 0.77, calculate the volatility (standard deviation) of a portfolio that is 80% invested in stock A and 20% invested in stock B. Year 2008 2009 2010 2011 2012 2013 Realized Returns Stock A Stock B - 2% 12% 12% 31% 1% 8% - 1% - 5% 3% - 13% 13% 34% The standard deviation of the portfolio is %. (Round to two decimal places.)