Year % net 1999 79.97245 2000 81.64213 2001 83.45605 2002 83.40459 2003 83.68168 2004 81.99364 2005 80.63589 2006 81.34277 2007 82.16796 2008 82.26676 2009 82.06513 2010 84.09228 2011 85.73788 2012 86.24599 2013 88.22682 2014 88.81447 2015 89.01455 2016 88.20588 2017 88.63549 2018 88.08639