Year	1=extremely inefficient to 7=extremely efficient
2007	3.27173913043478
2008	3.14753116858917
2009	3.2774249196
2010	3.3455820507
2011	3.3
2012	3.4
2013	3.6
2014	3.6
2015	3.5667860526643
2016	3.6
2017	4.1