Year % (national estimate) 1963 21.75 1973 23.23 1984 21.98 2000 38.96 2001 36.982 2002 35.385 2003 35.708 2004 32.524 2005 36.559 2006 37.282 2007 38.969 2008 37.67 2009 36.128 2010 34.212 2011 33.861 2012 38.74 2013 39.837 2014 38.141 2015 37.261 2016 32.441 2017 32.718 2018 35.407 2019 38.238 2020 37.409 2021 40.512 2022 36.69 2023 32.68