Year Percent 2003-01-01 0.278855 2004-01-01 0.285271 2005-01-01 0.321439 2006-01-01 0.317917 2007-01-01 0.345609 2008-01-01 0.328860 2009-01-01 0.338976 2010-01-01 0.295259 2011-01-01 0.369998 2012-01-01 0.258856