Year	1=extremely inefficient to 7=extremely efficient
2007	2.77837804122512
2008	2.79964608728908
2009	3.13795427302
2010	3.634327227775
2011	3.55
2012	3.58
2013	3.6
2014	3.56
2015	3.41695766106568
2016	3.43333333333333
2017	3.65