Year	Ratio
1971-01-01	0.985230028629303
1972-01-01	0.987030029296875
1973-01-01	0.989440023899078
1974-01-01	0.990010023117065
1975-01-01	0.991129994392395
1976-01-01	0.993009984493256
1977-01-01	0.992529988288879
1978-01-01	0.992479979991913
1979-01-01	0.991169989109039
1980-01-01	0.993939995765686
1981-01-01	0.995959997177124
1982-01-01	0.997879981994629
1983-01-01	0.996330022811890
1984-01-01	0.997290015220642
1985-01-01	0.996919989585876
1986-01-01	0.996060013771057
1987-01-01	0.991869986057281
1988-01-01	0.995779991149902
1989-01-01	0.995850026607513
1990-01-01	1.001080036163330
1991-01-01	0.998040020465851
1992-01-01	0.998629987239838
1993-01-01	1.027709960937500
1994-01-01	1.039180040359500
1995-01-01	0.985289990901947
1996-01-01	0.989340007305145
1997-01-01	0.995859980583191
1998-01-01	0.988439977169037
1999-01-01	0.993640005588531
2000-01-01	0.999379992485046
2001-01-01	0.993350028991699
2002-01-01	0.980820000171661
2003-01-01	0.991869986057281
2004-01-01	0.994040012359619
2005-01-01	0.989210009574890
2006-01-01	0.988489985466003
2007-01-01	0.988510012626648
2008-01-01	0.988150000572205
2009-01-01	0.988039970397949
2010-01-01	0.989530026912689
2011-01-01	0.987219989299774
2012-01-01	0.989090025424957
2013-01-01	0.991280019283295
2014-01-01	0.991069972515106
2015-01-01	0.992269992828369