Year	Overall average
2004	45.2444445333333
2005	47.8222221333333
2006	48.4188034615385
2007	47.7350426923077
2008	47.6068374358974
2009	47.6954733333333
2010	49.3621401234568
2011	51.1111108641975
2012	51.8106995061728
2013	51.0153256704981
2014	51.2068965517241
2015	52.6053701149425
2016	51.6858298850575
2017	52.1455931034483
2018	53.7356367816092