Year % (national estimate) 1960 85.21 1970 62.89 1978 58.47 1979 57.94 1980 68.04 1990 60.27 1991 71.181 1992 72.229 1993 73.303 1994 72.636 1995 71.812 1996 71.104 1997 70.851 1998 71.076 1999 69.3 2000 67.677 2001 65.527 2002 62.55 2003 62.284 2004 62.411 2005 62.451 2006 62.986 2007 62.617 2008 62.171 2009 60.793 2010 61.191 2011 60.647 2012 60.731 2013 59.749 2014 58.84 2015 57.892 2016 57.177 2017 56.72 2018 56.606 2019 57.361 2020 51.201 2021 56.189 2022 56.171 2023 55.875