Year % 2000 27.3 2001 27.1 2002 27.2 2003 28.7 2004 27 2005 27.4 2006 27.2 2007 32.3 2008 34.8 2009 34.9 2010 34.7 2011 35 2012 35 2013 34.8 2014 35 2015 34.8 2016 34.2 2017 34 2018 34.4 2019 33.9