Year Percent 1991 75.83 1992 75.13 1993 75.699 1994 75.628 1995 75.21 1996 75.177 1997 66.942 1998 75.094 1999 75.082 2000 66.896 2001 66.905 2002 62.889 2003 62.884 2004 68.789 2005 68.786 2006 74.325 2007 75.391 2008 77.856 2009 79.23 2010 79.11 2011 78.36 2012 75.07 2013 75.048 2014 73.018 2015 74.698 2016 75.222 2017 75.246 2018 75.186 2019 75.126 2020 75.065 2021 75.003 2022 74.941