Year	1=extremely inefficient to 7=extremely efficient
2007	4.59152228368646
2008	4.65269509842987
2009	4.65363581675
2010	4.70188668895
2011	4.6
2012	4.65
2013	4.8
2014	4.85
2015	4.93073858424468
2016	4.95
2017	5.4