Year	1=extremely inefficient to 7=extremely efficient
2007	2.96629213483146
2008	3.14240125553772
2009	3.6115227463
2010	3.8718297109
2011	3.4
2012	3.3
2013	3.5
2014	3.4
2015	2.99830258074014
2016	3
2017	3.2