Year	number
2003	10.795454545454545
2004	10.555555555555555
2005	10.547169811320755
2006	10.49056603773585
2007	9.981481481481481
2008	9.62962962962963
2009	9.37037037037037
2010	9.296296296296296
2011	9.166666666666666
2012	9.321428571428571
2013	9.290000000000001
2014	9.310491803278689
2015	9.11377049180328
2016	8.917868852459016
2017	8.729836065573771
2018	8.325081967213114
2019	7.951639344262295