Year	1=extremely inefficient to 7=extremely efficient
2007	3.2866222978773
2008	3.30489834026898
2009	3.5574073203284
2010	3.77396468104419
2011	3.70111111111111
2012	3.65714285714286
2013	3.61684210526316
2014	3.58913043478261
2015	3.61288128160295
2016	3.61444444444444
2017	3.72325581395349