Year % 2000 16.4 2001 15.5 2002 14.8 2003 15.9 2004 15.9 2005 17.2 2006 18.5 2007 19.1 2008 19.1 2009 19.5 2010 19 2011 19.7 2012 21.2 2013 22.6 2014 24.7 2015 25.6 2016 26 2017 24.9 2018 23.5 2019 22.1