Year	1=extremely inefficient to 7=extremely efficient
2007	3.82857142857143
2008	4.06923863571429
2009	4.2313578673
2010	4.2422063814
2011	4.1
2012	3.8
2013	4
2014	4.1
2015	4.14000890552998
2016	4.1
2017	4.2