Year % net 1998 81.49898 1999 81.41664 2000 82.4521 2001 83.15338 2002 85.84913 2003 86.50077 2004 89.16866 2005 91.35568 2006 91.90848 2007 90.83368 2008 90.16888 2009 90.11295 2010 90.16334 2011 91.0205 2012 91.11691 2013 91.59592 2014 91.97561 2015 93.14593 2016 93.42454 2017 93.28745