Year	number
2003	11.055555555555555
2004	10.64935064935065
2005	10.555555555555555
2006	10.472527472527473
2007	10.076923076923077
2008	9.637362637362637
2009	9.25
2010	9.076086956521738
2011	8.771739130434783
2012	8.680851063829786
2013	8.572254901960786
2014	8.441274509803923
2015	8.249019607843138
2016	8.05343137254902
2017	7.9017647058823535
2018	7.48921568627451
2019	7.276568627450981