Year	1=extremely inefficient to 7=extremely efficient
2007	3.02631578947368
2008	2.81546982306831
2009	3.2169418477
2010	3.8306591429
2011	4
2012	4.2
2013	4
2014	3.6
2015	3.40723809174129
2016	3.4
2017	3.4