Year % 1984 89.90532 1985 89.87323 1986 89.03695 1987 89.12784 1988 87.92429 1989 88.43842 1990 88.81403 1991 89.71295 1992 91.0167 1993 92.09074 1994 92.24 1995 92.49052 1996 94.32606 1997 95.0469 1998 95.68417 1999 96.26852 2000 96.55731 2001 95.22386 2002 95.40443 2003 97.16392 2004 98.12679 2005 99.20574 2006 99.24303 2007 99.18136 2008 99.03711 2009 99.11782 2010 99.23867 2011 99.35684 2012 97.04944 2013 98.36089 2014 98.64004 2015 99.57214 2016 99.51249 2017 99.6464