Year % 2000 24.66797406844372 2001 24.194724872504363 2002 23.927078072623043 2003 23.569843763569946 2004 22.84372981270509 2005 22.52069701621096 2006 21.668635165343733 2007 21.173486309009668 2008 20.837603612201228 2009 20.409195175242917 2010 19.93681596631938 2011 19.3530461570388 2012 18.91573029710062 2013 18.54626437070781 2014 18.47893393437339 2015 18.192270870911308 2016 18.140419718775448 2017 17.645622838932486 2018 17.40918065919114 2019 17.01826928365141