Year % 2000 15.8 2001 15.3 2002 14.7 2003 13.8 2004 13.1 2005 12.7 2006 12.7 2007 12.3 2008 11.9 2009 11.9 2010 11.4 2011 10.8 2012 10.7 2013 10.2 2014 10.3 2015 10.1 2016 9.9 2017 9.2 2018 9.5 2019 9