Year % (national estimate) 1965 52.28 1975 66.73 1976 67.68 1982 66.7 1983 65.38 1984 64.73 1985 65.97 1986 67.3 1987 66.32 1989 69.29 1990 69.086 1991 65.84 1992 60.37 1993 54.906 1994 53.554 1995 45.458 1996 43.129 1997 41.078 1998 40.617 1999 42.284 2000 40.732 2001 52.358 2002 50.513 2003 50.623 2004 48.549 2005 50.204 2006 51.338 2007 52.241 2008 52.843 2009 51.022 2010 51.631 2011 52.984 2012 52.584 2013 54.497 2014 55.448 2015 55.135 2016 54.84 2017 54.702 2018 54.091 2019 55.016 2020 52.062 2021 54.041 2022 56.914 2023 57.474