Year % 2000 13.7 2001 14.4 2002 14.8 2003 14.3 2004 14.2 2005 13.6 2006 14 2007 13.5 2008 13.6 2009 13.7 2010 13.5 2011 13 2012 14 2013 13.4 2014 13.4 2015 13.2 2016 12.4 2017 12.9 2018 12.8 2019 12.7