Year	years
2003	2.7147058823529413
2004	2.6857142857142855
2005	2.8
2006	2.768292682926829
2007	2.768292682926829
2008	2.768292682926829
2009	2.75
2010	2.6523809523809527
2011	2.5738095238095235
2012	2.5428571428571427
2013	2.4826086956521736
2014	2.4717391304347824
2015	2.497826086956522
2016	2.4586956521739127
2017	2.4695652173913047
2018	2.4695652173913043
2019	2.4695652173913043