Year % (national estimate) 1972 35.92 1974 31.21 1976 29.54 1978 31.04 1979 30.01 1980 29.24 1981 28.37 1982 27.64 1983 31.4 1986 29.29 1987 28.89 1988 29.54 1989 30.57 1990 45.535 1991 46.103 1992 48.259 1993 51.06 1994 54.459 1995 55.008 1996 54.409 1997 53.089 1998 51.01 1999 52.419 2000 54.488 2001 54.082 2002 50.263 2003 51.78 2004 52.509 2005 53.567 2006 53.938 2007 52.634 2008 50.728 2009 51.012 2010 50.8 2011 48.234 2012 50 2013 49.534 2014 49.848 2015 49.268 2016 49.307 2017 49.414 2018 48.796 2019 48.187 2020 44.704 2021 45.604 2022 47.239