Year	1=extremely inefficient to 7=extremely efficient
2007	4.97297297297297
2008	4.78300623588071
2009	4.7663836725
2010	4.8142024382
2011	5
2012	5
2013	5
2014	5.2
2015	5.192853077051
2016	5.2
2017	5.1