Year	number
2003	8.625
2004	8.529411764705882
2005	8.588235294117647
2006	8.647058823529411
2007	8.647058823529411
2008	8.705882352941176
2009	8.470588235294118
2010	8.294117647058824
2011	7.882352941176471
2012	8.277777777777779
2013	8.711
2014	8.55
2015	8.35
2016	8.211
2017	8.211
2018	7.75
2019	7.288499999999999