Year Percent 1991 60.161 1992 57.679 1993 57.609 1994 57.487 1995 56.808 1996 57.482 1997 60.655 1998 60.404 1999 63.405 2000 65.405 2001 67.354 2002 59.936 2003 62.357 2004 62.554 2005 61.135 2006 58.816 2007 60.401 2008 60.342 2009 59.247 2010 60.333 2011 62.397 2012 64.78 2013 64.815 2014 66.606 2015 66.041 2016 65.506 2017 65.313 2018 65.106 2019 64.876 2020 64.632 2021 64.384 2022 64.114