Year	1=extremely inefficient to 7=extremely efficient
2007	4.79452578304338
2008	4.77067641483617
2009	4.83118133604231
2010	4.90051879195
2011	4.85576923076923
2012	4.82641509433962
2013	4.87547169811321
2014	4.89423076923077
2015	4.87713176635887
2016	4.882
2017	4.97647058823529