Year	1=extremely inefficient to 7=extremely efficient
2007	4.830210381536
2008	4.82342281425219
2009	4.90405788157369
2010	4.90986900671579
2011	4.8
2012	4.82631578947368
2013	4.89473684210526
2014	4.9421052631579
2015	4.88411051620375
2016	4.88947368421053
2017	5.01578947368421