Year % (national estimate) 1992 37.083 1993 32.747 1994 32.196 1995 35.339 1996 30.805 1997 32.411 1998 37.288 1999 38.567 2000 36.988 2001 34.404 2002 31.653 2003 29.856 2004 26.331 2005 24.37 2006 24.574 2007 24.401 2008 23.294 2009 20.018 2010 19.891 2011 19.715 2012 19.79 2013 23.048 2014 26.414 2015 28.101 2016 31.461 2017 32.934 2018 33.434 2019 32.796 2020 31.105 2021 30.88 2022 30.187 2023 30.721