Year % (national estimate) 1975 53.06 1990 69.926 1991 68.61 1992 66.091 1993 62.496 1994 61.328 1995 60.973 1996 52.439 1997 50.992 1998 50.581 1999 52.553 2000 53.636 2001 56.04 2002 56.01 2003 55.959 2004 54.945 2005 54.435 2006 54.939 2007 55.826 2008 55.876 2009 54.63 2010 61.389 2011 62.596 2012 63 2013 63.267 2014 63.796 2015 64.436 2016 65.085 2017 65.696 2018 66.231 2019 66.097 2020 64.556 2021 57.337 2022 58.532 2023 59.318