Year % (national estimate) 1960 63.26 1965 61.32 1970 58.1 1974 58.31 1976 57.42 1977 58.05 1978 57.93 1979 56.83 1981 66.02 1983 62.208 1984 71.318 1985 72.191 1986 71.65 1987 74.744 1988 73.282 1989 71.318 1990 70.372 1991 70.893 1992 71.024 1993 70.013 1994 65.853 1995 69.444 1996 70.769 1997 70.413 1998 71.584 1999 70.112 2000 68.756 2001 65.019 2002 67.038 2003 63.61 2004 63.914 2005 66.224 2006 69.313 2007 69.138 2008 68.212 2009 67.192 2010 63.93 2011 63.316 2012 60.949 2013 59.005 2014 58.806 2015 58.868 2016 61.221 2017 61.227 2018 60.813 2019 61.783 2020 60.367 2021 59.935 2022 62.885 2023 65.562