Year	1=extremely inefficient to 7=extremely efficient
2007	3.1449696949464
2008	3.09522756955293
2009	3.3744875936
2010	3.8021408336625
2011	3.65
2012	3.565
2013	3.43157894736842
2014	3.38888888888889
2015	3.4343382977437
2016	3.44444444444444
2017	3.625