Year	1=extremely inefficient to 7=extremely efficient
2007	5.88505747126437
2008	5.03133861550597
2009	4.5508315934
2010	4.5327634424
2011	4.4
2012	4.4
2013	4.4
2014	4.4
2015	4.48495185375214
2016	4.5
2017	4.6