Year % 2000 27.1 2001 26.2 2002 25.3 2003 24.8 2004 24 2005 23.1 2006 22.2 2007 21.5 2008 20.6 2009 19.7 2010 18.8 2011 17.8 2012 17 2013 16.1 2014 15.3 2015 14.7 2016 14.1 2017 13.5 2018 13 2019 12.7