Year % (national estimate) 1975 32.96 1976 34.65 1977 36.23 1978 38.48 1979 40.18 1980 42.8 1982 47.02 1983 47.39 1984 48.14 1985 46.02 1986 45.55 1987 47.85 1988 50.05 1989 51.88 1991 37.09 1992 41.28 1993 40.06 1994 40.41 1995 38.76 1996 39.65 1997 39.03 1998 37.66 1999 48.1 2000 46.89 2001 49.6 2002 47.7 2003 47.7 2004 48.1 2006 51.58 2007 50.76 2008 53.16 2009 51.57 2010 53.97 2011 54.51 2012 55.27 2013 55.55 2014 56.23 2015 58.04 2016 57.68 2017 57.21 2018 57.76 2019 58.32 2020 57.73 2021 60.963 2022 60.948