Year	1=extremely inefficient to 7=extremely efficient
2007	2.3972602739726
2008	2.39497075219679
2009	2.7986488178
2010	3.3405375351
2011	3.5
2012	3.6
2013	3.9
2014	3.7
2015	3.57378667975784
2016	3.6