Year	Overall average
2004	67.5061728888889
2005	69.2345679259259
2006	68.6666666666667
2007	68.7160494814815
2008	68.9382714074074
2009	68.4782606521739
2010	68.4178745652174
2011	68.3574879710145
2012	67.1980677536232
2013	66.7149758454106
2014	68.4299516908213
2015	69.0096724637681
2016	67.343002173913
2017	67.4154630434783
2018	69.178747826087