Year % 1995 9.72 1996 10.7 1997 8.49 1998 6.48 1999 5.7 2000 4.76 2001 4.71 2002 5.08 2003 5.69 2004 5.1 2005 5.08 2006 5.7 2007 4.99 2008 5.6 2009 4.62 2010 4.61 2011 4.6 2012 4.57 2013 4.57 2014 4.57 2016 4.57 2018 4.57 2019 4.57 2020 4.57 2021 4.57