Year % 1995 31.52 1996 31.46 1997 31.46 1998 31.46 1999 31.46 2000 31.46 2001 31.46 2002 31.44 2003 31.44 2004 31.44 2005 31.44 2006 31.44 2007 31.65 2008 31.65 2009 31.65 2010 31.65 2011 31.65 2012 31.66 2013 31.66 2015 31.66 2018 31.74 2020 31.74 2021 31.74