Year Percent 1991 67.588 1992 50.893 1993 48.174 1994 53.082 1995 54.93 1996 47.601 1997 49.37 1998 46.872 1999 47.69 2000 50.814 2001 50.714 2002 50.924 2003 44.656 2004 45.521 2005 49.74 2006 48.915 2007 49.119 2008 48.229 2009 48.135 2010 47.693 2011 47.375 2012 46.255 2013 46.447 2014 46.93 2015 45.972 2016 44.757 2017 45.248 2018 45.139 2019 45.027 2020 44.906 2021 44.781 2022 44.654