Year	1=extremely inefficient to 7=extremely efficient
2007	2.81818181818182
2008	2.93146376818182
2009	3.3806188898
2010	3.7897341669
2011	3.7
2012	3.5
2013	3.4
2014	3.6
2015	3.59803921381632
2016	3.6
2017	4