Year % 1995 30.63 1996 30.58 1997 30.58 1998 30.58 1999 30.58 2000 30.58 2001 30.58 2002 30.58 2003 30.58 2004 30.58 2005 30.58 2006 30.58 2007 30.59 2008 30.59 2009 30.59 2010 30.59 2011 30.59 2012 30.6 2013 30.57 2014 30.57 2015 30.57 2016 30.57 2017 30.59 2018 30.59 2019 30.59 2020 30.59 2021 30.59