Year Percent 1994 61.88865 1995 60.40602 1996 61.23593 1997 60.61031 1998 58.32728 1999 59.05884 2000 61.52191 2001 61.44248 2002 60.16209 2003 59.58051 2004 69.48011 2005 71.62905 2006 73.38574 2007 71.35039 2008 72.22819 2009 68.9941 2010 71.9512 2011 73.27279 2012 73.01775 2013 72.04029 2014 72.76888 2015 73.03021 2016 73.03021 2017 76.03391