Year	number
2003	12.0625
2004	11.4
2005	11.210526315789474
2006	11.017241379310345
2007	10.568965517241379
2008	10
2009	9.53448275862069
2010	9.39655172413793
2011	9.033898305084746
2012	8.933333333333334
2013	8.747121212121211
2014	8.68560606060606
2015	8.54
2016	8.363484848484848
2017	8.235151515151514
2018	7.703636363636363
2019	7.578939393939394