Year	number
2005	41.60606060606061
2006	41.029411764705884
2007	41.088235294117645
2008	41
2009	40.64705882352941
2010	40.61764705882353
2011	40.44117647058823
2012	40.42857142857143
2013	40.55555555555556
2014	40.861111111111114
2015	40.44444444444444
2016	39.75
2017	39.05555555555556
2018	39
2019	37.47222222222222