Year	number
2003	11.46875
2004	11.305555555555555
2005	11.511627906976743
2006	11.295454545454545
2007	11
2008	10.409090909090908
2009	9.886363636363637
2010	9.681818181818182
2011	9.136363636363637
2012	8.977777777777778
2013	8.814347826086957
2014	8.59695652173913
2015	8.584255319148935
2016	8.201276595744682
2017	7.818297872340425
2018	7.605531914893617
2019	7.51063829787234