Year % 1992 92.81828 1993 93.29727 1994 93.02475 1995 93.61681 1996 94.73616 1997 95.14419 1998 95.84454 1999 96.29754 2000 96.59308 2001 96.12393 2002 96.33255 2003 97.27022 2004 97.72596 2005 98.24187 2006 98.20124 2007 98.25778 2008 98.27214 2009 98.28455 2010 98.35818 2011 98.29802 2012 97.04813 2013 97.83622 2014 98.02717 2015 98.53174 2016 98.58311 2017 98.62727