Year	number
2003	11.202247191011235
2004	10.75257731958763
2005	10.669642857142858
2006	10.535087719298245
2007	10.166666666666666
2008	9.640350877192983
2009	9.156521739130435
2010	8.965217391304348
2011	8.591304347826087
2012	8.533898305084746
2013	8.439444444444446
2014	8.277857142857144
2015	8.121259842519686
2016	7.885433070866143
2017	7.692755905511812
2018	7.3456692913385835
2019	7.159133858267718