Year	Overall average
2004	75.9788361904762
2005	75.873016031746
2006	75.2910055555556
2007	76.7724868253968
2008	76.7195766666667
2009	77.7777776190476
2010	78.6772487301587
2011	78.4656082539683
2012	76.8253966666667
2013	76.4550264550265
2014	77.8835978835979
2015	79.1534492063492
2016	78.7301650793651
2017	75.7142888888889
2018	75.6084714285714