Year	1=extremely inefficient to 7=extremely efficient
2007	3.88709677419355
2008	3.73241524983315
2009	3.795863047
2010	3.6047335
2011	3
2012	3.1
2013	3.5
2014	3.1
2015	2.42851617336273
2016	2.4
2017	2.2