Year	1=extremely inefficient to 7=extremely efficient
2007	3.0575648118052
2008	3.02006285905774
2009	3.29037401654
2010	3.60697178016
2011	3.46666666666667
2012	3.47692307692308
2013	3.25
2014	3.06923076923077
2015	3.21804988869586
2016	3.23636363636364
2017	3.20909090909091