Year	Ratio
1971-01-01	1.017470002174380
1972-01-01	1.084509968757630
1973-01-01	0.952269971370697
1974-01-01	0.958959996700287
1975-01-01	0.933440029621124
1976-01-01	0.945179998874664
1977-01-01	0.947239995002747
1978-01-01	0.963029980659485
1979-01-01	0.958490014076233
1980-01-01	0.954649984836578
1981-01-01	0.960340023040771
1982-01-01	0.969160020351410
1983-01-01	0.981970012187958
1984-01-01	1.019749999046330
1985-01-01	1.011739969253540
1995-01-01	0.996810019016266
1997-01-01	0.998459994792938
2001-01-01	1.014590024948120
2002-01-01	1.040760040283200
2003-01-01	1.035539984703060
2004-01-01	1.062280058860780
2005-01-01	1.049209952354430
2006-01-01	1.074859976768490
2011-01-01	0.979839980602264
2012-01-01	0.966289997100830
2013-01-01	0.971710026264191
2014-01-01	0.968699991703033
2015-01-01	0.979690015316010