Year Percent 2000 0.51706 2001 0.44195 2002 0.38589 2003 0.41912 2004 0.41474 2005 0.38058 2006 0.35352 2007 0.3688 2008 0.40692 2009 0.41893 2010 0.46651 2011 0.49056 2012 0.60116 2013 0.58556 2014 0.53762 2015 0.51342 2016 0.522 2017 0.55954 2018 0.54637 2019 0.52263 2020 0.55944 2021 0.53362 2022 0.49569