Year Percent 2001 76.4458 2002 79.97782 2003 80.63946 2004 80.7404 2005 82.09046 2006 82.03125 2007 82.29331 2008 82.25571 2009 81.89872 2010 82.33465 2011 81.51011 2012 81.46786 2013 80.8881 2015 82.53882