Year	number
2004	5.382352941176471
2005	5.323529411764706
2006	5.314285714285714
2007	5.314285714285714
2008	5.285714285714286
2009	5.171428571428572
2010	4.9714285714285715
2011	4.914285714285715
2012	4.914285714285715
2013	4.975263157894737
2014	4.896315789473684
2015	4.87
2016	4.87
2017	4.843684210526316
2018	4.87
2019	4.87