Year	years
2003	3.0749999999999997
2004	3.0749999999999997
2005	2.9828571428571427
2006	2.9828571428571427
2007	2.9828571428571427
2008	2.9828571428571427
2009	2.9828571428571427
2010	3.031428571428571
2011	2.9828571428571427
2012	2.983333333333333
2013	2.915
2014	2.905
2015	2.8924999999999996
2016	2.88
2017	2.88
2018	2.88
2019	2.7924999999999995