Year	1=extremely inefficient to 7=extremely efficient
2007	4.125
2008	3.97500916985646
2009	3.8330901441
2010	4.1104709844
2011	4.1
2012	3.9
2013	4.2
2014	4.6
2015	4.55573244153717
2016	4.6
2017	4.2