Year	number
2003	12.428571428571429
2004	11.928571428571429
2005	11.866666666666667
2006	11.5
2007	10.625
2008	9.5
2009	8.294117647058824
2010	7.764705882352941
2011	7.176470588235294
2012	6.705882352941177
2013	6.117647058823529
2014	6.0588235294117645
2015	5.588235294117647
2016	5.470588235294118
2017	5.294117647058823
2018	4.882352941176471
2019	4.882352941176471