Year	Overall average
2004	72.7306969868173
2005	74.8022222787194
2006	74.5385876836158
2007	75.3295292090395
2008	75.7250093220339
2009	75.7815064595104
2010	75.8850848775895
2011	76.4406780225989
2012	74.9444444259259
2013	74.4259259259259
2014	74.6314814814815
2015	75.0926
2016	75.500005
2017	75.074075
2018	74.8888933333333