Year % net 2007 90.11097 2008 88.69125 2009 88.21265 2010 89.1713 2011 89.70999 2012 91.43744 2013 92.8049 2014 94.09132 2015 94.44588 2016 95.11214 2017 96.26941 2018 94.59704