Year % 1997 57.37 2001 57.37 2002 57.37 2003 57.37 2004 56.36 2005 56.36 2006 56.36 2007 55.39 2008 55.39 2009 55.39 2010 55.39 2011 55.39 2012 53.75 2013 53.75 2015 53.75 2016 53.75 2018 54.5 2020 54.46 2021 54.46