Year Percent 2000 23.74773 2001 23.29258 2002 22.84098 2003 22.39297 2004 21.9486 2005 21.50795 2006 21.08914 2007 20.67881 2008 20.27693 2009 19.88359 2010 19.49873 2011 19.12245 2012 18.75467 2013 18.39536 2014 18.04459 2015 17.70228 2016 17.3684 2017 17.04284 2018 16.72563 2019 16.41666 2020 16.11586 2021 16.14617 2022 16.17447