Year	number
2003	12.235294117647058
2004	11.75
2005	11.727272727272727
2006	11.347826086956522
2007	11.08695652173913
2008	10.26086956521739
2009	9.391304347826088
2010	9.08695652173913
2011	8.434782608695652
2012	8.5
2013	8.416666666666666
2014	8.125
2015	8.12
2016	7.72
2017	7.36
2018	7.24
2019	7.16