Year	Overall average
2004	65.3968254365079
2005	67.2618849206349
2006	67.227128820059
2007	67.8367551327434
2008	67.8072565486726
2009	68.0530776499508
2010	68.7364603048181
2011	69.0265486430678
2012	68.1676412475633
2013	67.4952107279693
2014	67.9846743295019
2015	68.7547994252874
2016	68.783533045977
2017	68.4578583333333
2018	69.4731862068966