Year	1=extremely inefficient to 7=extremely efficient
2007	4.18004477574242
2008	4.16304626685767
2009	4.26225150772
2010	4.34207053067059
2011	4.27647058823529
2012	4.225
2013	4.17647058823529
2014	4.03529411764706
2015	4.17444682885452
2016	4.16666666666667
2017	4.25