Year	1=extremely inefficient to 7=extremely efficient
2007	4.88059701492537
2008	4.83591327064677
2009	4.7248130335
2010	4.9239495579
2011	4.9
2012	4.8
2013	4.8
2014	4.9
2015	4.97514409372362
2016	5
2017	5.2