Year scale 0 - 100 2004 71.42857107142856 2005 73.57142857142857 2006 73.69047607142856 2007 73.79310310344826 2008 74.94252793103448 2009 74.44444466666667 2010 76.83333400000001 2011 76.88888866666666 2012 76.55555533333333 2013 72.55208333333333 2014 71.71874999999997 2015 75.208353125 2016 74.16669375000001 2017 75.729175 2018 76.04168437499997 2019 74.89583749999997 2020 73.541671875