Year % 2000 9.3 2001 9.1 2002 9 2003 8.8 2004 8.4 2005 8.3 2006 8 2007 8 2008 7.8 2009 7.8 2010 7.6 2011 7.7 2012 7.7 2013 7.4 2014 7.3 2015 7.3 2016 7 2017 7.1 2018 6.9 2019 6.8