Year	1=extremely inefficient to 7=extremely efficient
2007	2.93478260869565
2008	2.77933355031056
2009	3.1154635776
2010	3.7274587674
2011	3.7
2012	3.5
2013	3.4
2014	3.5
2015	3.45630013143956
2016	3.5
2017	3.5