Year	number
2003	9.609756097560975
2004	9.142857142857142
2005	9.162790697674419
2006	8.777777777777779
2007	8.422222222222222
2008	7.586956521739131
2009	7.042553191489362
2010	6.808510638297872
2011	6.48936170212766
2012	6.416666666666667
2013	5.979591836734694
2014	5.775510204081633
2015	5.510204081632653
2016	5.408163265306122
2017	5.326530612244898
2018	5.34
2019	5.26