Year Percent 1991 54.761 1992 53.212 1993 53.22 1994 52.233 1995 54.242 1996 53.609 1997 53.542 1998 53.7 1999 53.353 2000 53.174 2001 51.984 2002 50.401 2003 45.427 2004 41.864 2005 42.94 2006 42.127 2007 44.981 2008 45.664 2009 42.852 2010 42.888 2011 42.022 2012 40.545 2013 43.986 2014 46.579 2015 45.335 2016 43.869 2017 43.894 2018 43.621 2019 43.253 2020 42.862 2021 42.396 2022 41.921