Year % 1995 30.72 1997 30.72 2001 30.61 2002 30.61 2003 30.61 2004 30.61 2005 30.61 2006 30.61 2007 30.63 2008 30.63 2009 30.63 2010 30.63 2011 30.63 2012 30.63 2013 30.58 2015 30.58 2016 30.58 2017 30.58