Year % 1990 71.43427 1991 65.19398 1992 68.68164 1993 67.81289 1994 69.91075 1995 74.29016 1996 73.69192 1997 76.66238 1998 78.93345 1999 75.29654 2000 77.64986 2001 76.51487 2002 76.90848 2003 76.46788 2004 78.38869 2005 80.00375 2006 82.24978 2007 81.66039 2008 81.13477 2009 81.91137 2010 83.01964 2011 83.52479 2012 73.13349 2013 87.65609 2014 81.68693 2015 81.45609 2016 84.64194 2017 100