Year	1=extremely inefficient to 7=extremely efficient
2007	4.56410256410256
2008	4.89414583557873
2009	5.1197362182
2010	5.0179869094
2011	4.9
2012	4.7
2013	4.8
2014	4.9
2015	4.58738410514698
2016	4.6
2017	4.7