Year	1=extremely inefficient to 7=extremely efficient
2007	3.72313149368743
2008	3.69061082665854
2009	3.72184967581429
2010	3.81667127918889
2011	3.67777777777778
2012	3.575
2013	3.58888888888889
2014	3.42222222222222
2015	3.59241285856799
2016	3.58571428571429
2017	3.65