Year % 2001 6.42 2002 6.42 2003 6.42 2004 6.42 2005 6.42 2006 6.42 2007 6.66 2008 6.66 2009 6.66 2010 6.65 2011 6.64 2012 6.63 2013 6.7 2015 6.52 2016 6.52 2020 6.52 2021 6.51