Year Percent 1999-01-01 0.969690024852753 2001-01-01 0.937789976596832 2002-01-01 0.931159973144531 2003-01-01 0.944580018520355 2004-01-01 0.952350020408630 2005-01-01 0.941330015659332 2007-01-01 0.951210021972656 2008-01-01 0.932020008563995 2009-01-01 0.957009971141815 2011-01-01 0.929180026054382 2012-01-01 0.977670013904572 2013-01-01 0.951520025730133 2014-01-01 0.964219987392426 2015-01-01 0.974870026111603