Year % net 1996 83.76757 1997 83.66929 1998 83.12945 1999 83.49732 2000 84.72794 2001 85.95791 2002 86.40111 2003 86.71729 2004 85.97552 2005 85.98501 2006 86.26724 2007 86.46579 2008 86.73677 2009 86.63243 2010 87.86743 2011 88.30672 2012 88.28576 2013 89.42876 2014 89.87258 2015 90.14916 2016 89.83235 2017 90.23664 2018 89.98414