Year Percent 1991 68.069 1992 68.679 1993 67.222 1994 64.641 1995 64.167 1996 63.476 1997 65.67 1998 65.638 1999 66.761 2000 66.834 2001 67.506 2002 64.612 2003 66.162 2004 69.296 2005 63.742 2006 67.394 2007 68.487 2008 68.585 2009 68.277 2010 68.618 2011 70.035 2012 68.147 2013 71.187 2014 68.304 2015 71.44 2016 71.616 2017 71.627 2018 71.714 2019 72.217 2020 72.583 2021 73.119 2022 73.625