Year	1=extremely inefficient to 7=extremely efficient
2007	4.25794079570645
2008	4.27622378253703
2009	4.37342168133636
2010	4.41543628747556
2011	4.36444444444444
2012	4.36444444444444
2013	4.46590909090909
2014	4.54318181818182
2015	4.51047115721782
2016	4.51111111111111
2017	4.65