Year	number
2003	11.204081632653061
2004	10.764150943396226
2005	10.632
2006	10.488188976377952
2007	10.173228346456693
2008	9.67716535433071
2009	9.2109375
2010	9.0390625
2011	8.651162790697674
2012	8.590909090909092
2013	8.459361702127659
2014	8.30290780141844
2015	8.162676056338029
2016	7.9468309859154935
2017	7.767464788732394
2018	7.442957746478874
2019	7.262042253521127