Year	number
2004	5.428571428571429
2005	5.428571428571429
2006	5.545454545454546
2007	5.636363636363637
2008	5.636363636363637
2009	5.636363636363637
2010	5.454545454545454
2011	5.454545454545454
2012	5.521739130434782
2013	5.5
2014	5.5
2015	5.5
2016	5.5
2017	5.461538461538462
2018	5.367307692307692
2019	5.367307692307692