Year	number
2004	5.764705882352941
2005	5.647058823529412
2006	5.611111111111111
2007	5.611111111111111
2008	5.631578947368421
2009	5.526315789473684
2010	5.368421052631579
2011	5.4
2012	5.4
2013	5.35
2014	5.3
2015	5.25
2016	5.25
2017	5.25
2018	5.3
2019	5.3