Year % 1972 39.43516 1985 60.6377 1986 65.82903 1997 65.46067 1998 65.3677 1999 63.74665 2000 67.19871 2001 76.05728 2002 77.3705 2003 72.87447 2004 70.59017 2005 83.35778 2006 75.58115 2007 81.70544 2008 86.6452 2009 87.76142 2010 86.94312 2011 85.89064 2012 85.87698 2013 86.06502 2014 88.10427 2015 88.47667