Year % 2000 24.173827708957702 2001 24.158374267865213 2002 23.935746832577504 2003 23.711641816610914 2004 23.449961058786137 2005 22.93574677690539 2006 22.39499985370233 2007 21.94426529477543 2008 21.226955272102582 2009 20.84245689444594 2010 20.268081119663503 2011 19.78930902190875 2012 19.520209748644234 2013 19.15346770586749 2014 18.93183714426036 2015 18.608093418859884 2016 18.434240294822775 2017 18.250189721751035 2018 18.13136800650779 2019 17.898789487079302