Year	1=extremely inefficient to 7=extremely efficient
2007	5.06382978723404
2008	4.75333441025285
2009	4.5894013713
2010	4.574209175
2011	4.6
2012	4.9
2013	5.1
2014	5.2
2015	5.03502729475036
2016	5
2017	5.2