Year	1=extremely inefficient to 7=extremely efficient
2007	4.09677419354839
2008	3.95059776753493
2009	4.02911865
2010	4.1557257112
2011	4
2012	3.7
2013	3.5
2014	3.5
2015	3.53491472135788
2016	3.5
2017	3.3