Year	Ratio
1971-01-01	0.645659983158112
1972-01-01	0.668649971485138
1973-01-01	0.682479977607727
1974-01-01	0.696200013160706
1975-01-01	0.709469974040985
1976-01-01	0.722450017929077
1977-01-01	0.738520026206970
1978-01-01	0.760299980640411
1979-01-01	0.788929998874664
1980-01-01	0.843439996242523
1981-01-01	0.880580008029938
1982-01-01	0.890730023384094
1983-01-01	0.899930000305176
1984-01-01	0.924610018730164
1985-01-01	0.942770004272461
1986-01-01	0.956300020217896
1987-01-01	0.982659995555878
1988-01-01	0.954270005226135
1989-01-01	0.958739995956421
1990-01-01	0.962840020656586
1991-01-01	0.970260024070740
1992-01-01	0.974889993667603
1993-01-01	0.983759999275208
1994-01-01	0.977699995040894
1995-01-01	0.998459994792938
1996-01-01	1.000259995460510
1997-01-01	0.996249973773956
1998-01-01	0.995899975299835
1999-01-01	0.996410012245178
2000-01-01	1.006549954414370
2001-01-01	1.016049981117250
2002-01-01	1.019119977951050
2003-01-01	1.023650050163270
2004-01-01	1.024639964103700
2005-01-01	1.022719979286190
2006-01-01	1.010499954223630
2007-01-01	1.003669977188110
2008-01-01	1.000010013580320
2009-01-01	0.997070014476776
2010-01-01	0.994780004024506
2011-01-01	0.991419970989227
2012-01-01	0.993309974670410
2013-01-01	0.996089994907379
2014-01-01	0.999270021915436
2015-01-01	1.001420021057130