Year	1=extremely inefficient to 7=extremely efficient
2007	2.61904761904762
2008	2.75486546320346
2009	3.1220711537
2010	3.2826869305
2011	3.3
2012	3.3
2013	3.1
2014	3.3
2015	3.69544748067856
2016	3.7
2017	3.5