Year % net 1998 28.17994 1999 28.48255 2000 29.20372 2001 30.0482 2002 30.93173 2003 31.96367 2004 33.21712 2005 33.70621 2006 35.34739 2007 36.36992 2008 37.2808 2009 38.16652 2010 39.19138 2011 39.43157 2012 40.11857 2013 40.84889 2014 41.23964 2015 41.49234 2016 42.55001 2017 42.67926 2018 43.6993