Year Percent 1995 80.32176 1996 80.98335 1997 81.50697 1998 82.62664 1999 83.63014 2001 88.62489 2002 88.52596 2003 88.79543 2004 89.15249 2005 89.41141 2006 90.166 2007 90.63128 2008 91.08536 2009 91.16124 2010 91.12975 2015 89.60433 2016 91.33808