Year % (national estimate) 1961 75.33 1971 64.1 1980 51.63 1981 63.46 1982 55.22 1983 56.66 1984 59.99 1985 58.69 1986 59.36 1987 61.53 1988 61.14 1989 60.95 1990 60.14 1991 60.49 1992 61.65 1993 58.2 1994 59.216 1995 58.871 1996 56.375 1997 55.448 1998 55.503 1999 54.171 2000 51.491 2001 50.147 2002 51.011 2003 49.742 2004 53.167 2005 54.391 2006 54.372 2007 56.289 2008 56.426 2009 56.49 2010 54.229 2011 55.058 2012 55.563 2013 55.446 2014 55.625 2015 54.307 2016 54.788 2017 53.872 2018 54.038 2019 52.69 2020 53.196 2021 52.105 2022 53.702 2023 56.104