Year % 1995 68.1 1997 68.1 2001 68.09 2002 68.09 2003 67.2 2004 67.2 2005 67.2 2006 67.2 2007 66.18 2008 66.18 2009 66.18 2010 66.18 2011 66.18 2012 66.18 2013 63.21 2015 63.21 2016 63.21 2017 63.21