Year	number
2003	11.130434782608695
2004	11.066666666666666
2005	11.1875
2006	10.84375
2007	10.71875
2008	10.34375
2009	9.93939393939394
2010	9.696969696969697
2011	9.06060606060606
2012	9.11111111111111
2013	8.837837837837839
2014	8.64864864864865
2015	8.5
2016	8.394736842105264
2017	8.18421052631579
2018	8.105263157894736
2019	7.921052631578948