Year % 1990 78.11163 1991 69.51928 1992 75.30747 1993 72.06669 1994 78.19644 1995 81.01266 1996 81.59616 1997 81.32432 1998 83.69997 1999 80.66524 2000 83.91581 2001 85.36794 2002 86.49322 2003 84.93557 2004 85.85849 2005 86.93463 2006 90.44905 2007 89.31593 2008 88.4575 2009 89.07857 2010 88.72482 2011 91.97439 2012 83.33333 2013 92.85936 2014 90.04713 2015 90.27535 2016 90.49404 2017 98.79534