Year % 1993 9.53 1995 8.65 1996 6.05 1997 5.88 1998 5.62 1999 6.64 2000 5 2001 4.75 2002 4.64 2003 4.5 2004 4.29 2005 4.29 2006 4.31 2007 4.26 2008 4.3 2009 4.37 2010 4.35 2011 4.29 2013 4.36 2015 4.39 2016 4.39 2017 4.42 2018 4.41 2019 4.42 2020 4.44 2021 4.46