Year	years
2003	3.34
2004	3.276190476190476
2005	3.295652173913044
2006	3.2833333333333337
2007	3.2320000000000007
2008	3.2319999999999998
2009	3.2319999999999998
2010	3.2320000000000007
2011	3.22
2012	3.2200000000000006
2013	3.115384615384616
2014	3.1000000000000005
2015	3.080769230769231
2016	3.0615384615384618
2017	3.0615384615384613
2018	3.0615384615384618
2019	3.0615384615384618