Year % net 1998 60.64323 1999 62.02128 2000 62.7066 2001 63.43926 2002 63.31473 2003 64.59492 2004 66.01198 2005 66.81065 2006 67.89524 2007 69.96361 2008 69.91141 2009 71.80212 2010 73.82039 2011 75.38487 2012 74.56589 2013 76.11492 2014 78.70527 2015 78.39649 2016 78.45527 2017 78.14456 2018 78.31161