Year % (national estimate) 1965 54.73 1975 46.33 1992 44.04 1997 32.6 2000 35.947 2001 36.836 2002 35.071 2003 32.734 2004 33.291 2005 31.118 2006 31.305 2007 31.717 2008 33.984 2009 34.023 2010 35.491 2011 33.856 2012 35.294 2013 34.335 2014 31.538 2015 30.494 2016 27.984 2017 30.522 2018 27.842 2019 27.576 2020 25.353 2021 24.221 2022 26.192 2023 24.357