Year % 2000 16.5 2001 16.2 2002 15.6 2003 15.5 2004 15.2 2005 14.8 2006 14.6 2007 14.5 2008 13.9 2009 13.6 2010 13.2 2011 12.7 2012 12.3 2013 12.3 2014 11.9 2015 11.5 2016 11.2 2017 10.9 2018 10.7 2019 10.4