Year % 1998 98.05798 1999 100 2000 99.37038 2004 99.36949 2005 98.54758 2006 96.60087 2007 96.92686 2008 95.40396 2009 94.39684 2010 94.06525 2011 92.08678 2012 90.57679 2013 88.60501 2014 87.73989 2015 87.06874 2016 90.41548