Year % net 1999 60.00137 2000 61.25926 2001 63.36285 2002 65.09736 2004 64.48259 2005 64.54137 2008 66.10004 2009 66.36634 2010 68.58165 2011 68.39254 2013 72.99069 2014 71.80451 2015 72.08741 2017 65.94409