Year	1=extremely inefficient to 7=extremely efficient
2007	3.86885245901639
2008	3.44835693613012
2009	3.5257106111
2010	4.0638000294
2011	4.1
2012	3.7
2013	3.7
2014	3.5
2015	3.49554629481357
2016	3.5
2017	3.6