Year Percent 1991 70.445 1992 69.979 1993 69.553 1994 70.467 1995 71.314 1996 73.11 1997 74.351 1998 75.507 1999 75.069 2000 72.551 2001 73.421 2002 74.239 2003 75.026 2004 75.771 2005 76.488 2006 76.67 2007 76.815 2008 77.432 2009 74.655 2010 71.85 2011 73.809 2012 74.892 2013 74.692 2014 74.477 2015 74.244 2016 73.986 2017 73.862 2018 73.752 2019 73.66 2020 73.591 2021 73.543 2022 73.512