Year % 2000 9.6 2001 9.5 2002 9.3 2003 9.3 2004 9.2 2005 8.7 2006 8.9 2007 9 2008 8.7 2009 8.7 2010 8.8 2011 8.7 2012 8.9 2013 8.7 2014 8.1 2015 8.1 2016 8.2 2017 8 2018 8 2019 8