Year	1=extremely inefficient to 7=extremely efficient
2007	3.37978780926791
2008	3.44389370098278
2009	3.66733487550526
2010	3.84661201947949
2011	3.795
2012	3.75121951219512
2013	3.76829268292683
2014	3.74871794871795
2015	3.77211753732517
2016	3.76666666666667
2017	3.92222222222222