Year	number
2003	12.571428571428571
2004	12.0625
2005	11.764705882352942
2006	11.764705882352942
2007	10.947368421052632
2008	10.105263157894736
2009	9.789473684210526
2010	9.894736842105264
2011	9.75
2012	9.714285714285714
2013	9.476190476190476
2014	9.380952380952381
2015	9.238095238095237
2016	8.904761904761905
2017	8.428571428571429
2018	7.809523809523809
2019	6.904761904761905