Year	Ratio
1971-01-01	0.451330006122589
1972-01-01	0.404370009899139
1973-01-01	0.395440012216568
1974-01-01	0.364010006189346
1975-01-01	0.368449985980988
1976-01-01	0.340739995241165
1977-01-01	0.385039985179901
1979-01-01	0.438870012760162
1980-01-01	0.453689992427826
1982-01-01	0.504230022430420
1983-01-01	0.539950013160706
1984-01-01	0.557929992675781
1992-01-01	0.672360002994537
1993-01-01	0.718079984188080
1994-01-01	0.749870002269745
2003-01-01	0.973169982433319
2004-01-01	1.014369964599610
2005-01-01	1.009179949760440
2006-01-01	0.989960014820099
2007-01-01	0.969829976558685
2008-01-01	0.968699991703033
2009-01-01	0.957059979438782
2010-01-01	0.994719982147217
2011-01-01	1.057350039482120
2012-01-01	1.052860021591190
2013-01-01	1.094320058822630
2014-01-01	1.114269971847530
2015-01-01	1.126189947128300
2016-01-01	1.140030026435850