Year % 2000 28.987868684875703 2001 28.826228444777744 2002 28.590606280790418 2003 28.31138817334228 2004 27.361997315653976 2005 27.43364989279905 2006 27.68292458474821 2007 27.871056915281162 2008 28.021657908126027 2009 27.94622670985071 2010 28.04905119012641 2011 27.852462851297325 2012 27.51992004791682 2013 26.573006199271205 2014 25.86062826766787 2015 26.056448150382995 2016 25.923940359828052 2017 25.580065210879518 2018 25.339537793515262 2019 25.17883537929601