Year % net 1999 36.36152 2000 37.52671 2001 38.53731 2002 40.01771 2003 41.87168 2004 43.01751 2005 43.98605 2006 45.25852 2007 47.2152 2008 48.70133 2009 49.10457 2010 51.31839 2011 53.42572 2012 55.10399 2013 56.63724 2014 57.06014 2015 57.52835 2016 58.23183 2017 59.64078 2018 59.73422