Year	number
2004	5.533333333333333
2005	5.6
2006	5.761904761904762
2007	5.761904761904762
2008	5.619047619047619
2009	5.476190476190476
2010	5.476190476190476
2011	5.476190476190476
2012	5.476190476190476
2013	5.786818181818182
2014	5.741363636363636
2015	5.741363636363636
2016	5.741363636363636
2017	5.762272727272727
2018	5.716818181818182
2019	5.625909090909091