Year	1=extremely inefficient to 7=extremely efficient
2007	2.72972972972973
2008	3.50816577701874
2009	3.7891862286
2010	3.7982213021
2011	3.7
2012	3.4
2013	3.7
2014	3.4
2015	3.38664315179154
2016	3.4
2017	3.1