Year	1=extremely inefficient to 7=extremely efficient
2007	3.02577319587629
2008	3.03436718232771
2009	3.2660323356
2010	3.5243026163
2011	3.5
2012	3.9
2013	4
2014	3.9
2015	4.22222227369036
2016	4.2
2017	3.9