Year	Ratio
1971-01-01	0.987510025501251
1972-01-01	0.993950009346008
1973-01-01	0.995469987392426
1974-01-01	0.998979985713959
1975-01-01	1.006809949874880
1976-01-01	0.978020012378693
1977-01-01	0.995570003986359
1978-01-01	0.979480028152466
1979-01-01	0.976870000362396
1980-01-01	0.978760004043579
1981-01-01	0.991370022296906
1982-01-01	0.993359982967377
1983-01-01	0.993290007114410
1984-01-01	0.995389997959137
1985-01-01	0.994570016860962
1986-01-01	0.995159983634949
1987-01-01	0.993619978427887
1988-01-01	0.994700014591217
1989-01-01	0.992770016193390
1990-01-01	0.996999979019165
1991-01-01	1.002200007438660
1992-01-01	1.004719972610470
1993-01-01	0.999700009822845
1994-01-01	0.997300028800964
1995-01-01	0.999149978160858
1996-01-01	0.993319988250732
1997-01-01	0.998380005359650
1998-01-01	0.986230015754700
1999-01-01	0.983399987220764
2000-01-01	0.979170024394989
2001-01-01	0.978649973869324
2002-01-01	0.976639986038208
2003-01-01	0.975880026817322
2004-01-01	0.961329996585846
2005-01-01	0.959339976310730
2006-01-01	0.962379992008209
2007-01-01	0.961589992046356
2008-01-01	0.969649970531464
2009-01-01	0.966809988021851
2010-01-01	0.957979977130890
2011-01-01	0.952950000762939
2012-01-01	0.958959996700287
2013-01-01	0.955280005931854
2014-01-01	0.965650022029877
2015-01-01	0.967840015888214
2016-01-01	0.969150006771088