Year	number
2003	11.142857142857142
2004	10.69811320754717
2005	10.576
2006	10.433070866141732
2007	10.118110236220472
2008	9.622047244094489
2009	9.15625
2010	8.9765625
2011	8.589147286821705
2012	8.530303030303031
2013	8.390070921985815
2014	8.24822695035461
2015	8.105633802816902
2016	7.887323943661972
2017	7.711267605633803
2018	7.401408450704225
2019	7.225352112676056