Year % (national estimate) 1960 76.55 1970 75.97 1979 63.86 1980 56.25 1983 59.7 1984 61.79 1985 62.44 1986 59.4 1988 63.8 1989 64.7 1990 60.66 1991 62.93 1993 67.7 1994 65.91 1995 66.75 1996 62.5 1997 64.96 1998 64.59 1999 64.5 2000 60.5 2002 62.3 2003 62.48 2004 63.2 2005 62.07 2006 60.5 2007 61.03 2008 65.21 2009 65.06 2010 62.233 2011 58.254 2012 60.41 2013 58.802 2014 57.394 2015 55.319 2016 55.33 2017 53.912 2018 57.047 2019 56.512 2020 56.762 2021 51.861 2022 57.454 2023 51.474