Year % net 1998 93.56284 1999 92.84634 2000 92.87232 2001 93.68062 2002 92.96308 2003 92.80361 2004 92.59098 2005 92.23515 2006 92.33927 2007 92.79725 2008 92.25149 2009 92.67095 2010 92.95217 2011 92.8682 2012 92.91699 2013 92.64227 2014 92.28672 2015 91.87042 2016 91.2322 2017 91.3002