Year	number
2003	9.090909090909092
2004	8.909090909090908
2005	8.909090909090908
2006	8.454545454545455
2007	8.363636363636363
2008	7.090909090909091
2009	6.363636363636363
2010	6.181818181818182
2011	6.090909090909091
2012	6.2727272727272725
2013	6
2014	5.818181818181818
2015	5.545454545454546
2016	5.545454545454546
2017	5.545454545454546
2018	5.7272727272727275
2019	5.545454545454546