Year % 1975 67.57912 1999 96.35379 2000 94.79813 2001 96.77436 2004 93.94472 2005 94.0255 2006 95.15405 2007 94.6803 2008 100 2009 98.51344 2010 93.15442 2011 89.36794 2012 97.64427 2013 89.55101 2014 88.42598 2015 95.50459 2016 94.209 2017 94.44697