Year	Overall average
2004	57.7777778787879
2005	63.6363636363636
2006	64.4444445454545
2007	65.0505051515152
2008	66.0606057575758
2009	62.0370366666667
2010	61.2500002777778
2011	64.0740741666667
2012	63.7037038888889
2013	63.4259259259259
2014	63.4259259259259
2015	64.4444583333333
2016	62.1296416666667
2017	61.0185194444444
2018	59.8611194444444