Year	years
2003	3.2555555555555555
2004	3.2421052631578946
2005	3.2039999999999997
2006	3.1079999999999997
2007	3.053846153846154
2008	3.053846153846154
2009	3.053846153846154
2010	3.053846153846154
2011	2.9592592592592593
2012	2.9592592592592593
2013	2.910344827586207
2014	2.910344827586207
2015	2.910344827586207
2016	2.910344827586207
2017	2.8689655172413793
2018	2.8689655172413793
2019	2.868965517241379