Year	number
2003	8.6875
2004	8.588235294117647
2005	8.647058823529411
2006	8.705882352941176
2007	8.705882352941176
2008	8.764705882352942
2009	8.529411764705882
2010	8.352941176470589
2011	7.9411764705882355
2012	8.333333333333334
2013	8.761
2014	8.6
2015	8.4
2016	8.261
2017	8.261
2018	7.8
2019	7.338499999999999