Year % net 1988 31.0312 2003 22.91929 2004 24.63753 2005 29.40496 2007 30.24359 2008 29.76378 2009 30.11287 2010 33.73971 2011 43.27554 2013 50.34084 2014 61.45179 2015 61.7004