Year	Ratio
1970-01-01	0.732789993286133
1971-01-01	0.756079971790314
1972-01-01	0.769739985466003
1973-01-01	0.790579974651337
1974-01-01	0.829439997673035
1975-01-01	0.859430015087128
1976-01-01	0.877399981021881
1977-01-01	0.886799991130829
1978-01-01	0.893369972705841
1979-01-01	0.906899988651276
1980-01-01	0.920849978923798
1981-01-01	0.932590007781982
1982-01-01	0.939869999885559
1983-01-01	0.939920008182526
1984-01-01	0.948830008506775
1985-01-01	0.955190002918243
1986-01-01	0.951340019702911
1987-01-01	0.954209983348846
1988-01-01	0.964590013027191
1989-01-01	0.962029993534088
1990-01-01	0.965399980545044
1991-01-01	0.970700025558472
1992-01-01	0.970920026302338
1993-01-01	0.978739976882935
1994-01-01	0.985610008239746
1995-01-01	0.983200013637543
1998-01-01	0.980769991874695
1999-01-01	0.971599996089935
2000-01-01	0.985750019550323
2001-01-01	0.980329990386963
2002-01-01	0.949630022048950
2003-01-01	0.952889978885651
2004-01-01	0.944130003452301
2005-01-01	0.960799992084503
2006-01-01	0.973070025444031
2007-01-01	0.986479997634888
2008-01-01	0.980570018291473
2009-01-01	0.979589998722076
2012-01-01	1.008059978485110
2014-01-01	1.006649971008300
2015-01-01	0.998929977416992
2016-01-01	1.003190040588380