Year	number
2003	11.46875
2004	11.277777777777779
2005	11.488372093023257
2006	11.272727272727273
2007	10.977272727272727
2008	10.386363636363637
2009	9.863636363636363
2010	9.659090909090908
2011	9.113636363636363
2012	8.955555555555556
2013	8.782608695652174
2014	8.565217391304348
2015	8.553191489361701
2016	8.170212765957446
2017	7.787234042553192
2018	7.595744680851064
2019	7.51063829787234