Year % (national estimate) 1962 48.33 1968 51.07 1975 46.1 1979 47.59 1980 47.05 1981 46.12 1982 46.28 1983 53.219 1984 52.015 1985 51.406 1986 51.282 1987 49.58 1988 46.415 1989 45.247 1990 44.569 1991 39.915 1992 39.48 1993 38.033 1994 36.393 1995 35.49 1996 34.963 1997 33.914 1998 33.947 1999 35.81 2000 35.481 2001 35.753 2002 36.888 2003 37.143 2004 36.695 2005 34.059 2006 34.116 2007 34.627 2008 34.732 2009 35.597 2010 35.017 2011 33.985 2012 33.375 2013 35.318 2014 34.38 2015 34.882 2016 34.915 2017 34.982 2018 35.671 2019 34.885 2020 33.859 2021 37.974 2022 40.345 2023 42.507