Year % 1999 9.64 2000 9.6 2001 10.02 2002 5.06 2003 4.95 2004 4.96 2005 4.87 2006 4.91 2007 4.68 2008 4.57 2009 4.5 2010 4.32 2011 4.4 2012 4.4 2013 4.47 2014 4.03 2015 4.13 2016 3.98 2017 4.33 2018 3.84 2019 4.09 2020 4.03 2021 4.06