Year % (national estimate) 1997 49.75 1998 49.6 1999 49.2 2000 73.711 2001 72.286 2002 70.948 2003 69.766 2004 68.607 2005 67.791 2006 67.12 2007 66.38 2008 65.6 2009 65.15 2010 64.85 2011 64.5 2012 64.9 2013 65.3 2014 65.6 2015 65.7 2016 66.6 2017 66.9 2018 66.8 2019 67.344 2020 65.766 2021 66.374 2022 66.2