Year % 1997 39.37 1999 39.37 2000 39.09 2001 39.09 2002 39.09 2003 39.09 2004 39.09 2005 39.09 2006 39.09 2007 43.08 2008 43.91 2009 43.85 2010 44.85 2012 45.66 2013 46.05 2018 41.25 2019 41.25 2020 41.25 2021 41.25