Year	1=extremely inefficient to 7=extremely efficient
2007	3.76315789473684
2008	3.73997105263158
2009	4.0878089199
2010	4.2072354613
2011	3.9
2012	3.5
2013	3.4
2014	3.9
2015	3.48162278752578
2016	3.5
2017	2.8