Year	Overall average
2004	71.1924121680217
2005	73.1977779132791
2006	72.5202982926829
2007	73.8752846341463
2008	74.3901895121951
2009	74.3359888888889
2010	74.2682387262873
2011	75.2574527642277
2012	73.3862433862434
2013	71.4728682170543
2014	71.8888888888889
2015	72.4806255813954
2016	73.7726147286822
2017	74.0568496124031
2018	73.2816573643411