Year % 2000 13.6 2001 13.2 2002 12.9 2003 12.7 2004 12 2005 11.8 2006 11.4 2007 11.2 2008 10.9 2009 10.8 2010 10.4 2011 10.5 2012 10.4 2013 10 2014 9.8 2015 9.8 2016 9.3 2017 9.4 2018 9.1 2019 9