Year	Ratio
1971-01-01	0.964540004730225
1972-01-01	0.964209973812103
1973-01-01	0.963549971580505
1974-01-01	0.970130026340485
1975-01-01	0.973290026187897
1976-01-01	0.970979988574982
1977-01-01	0.975449979305267
1978-01-01	0.975109994411469
1979-01-01	0.968219995498657
1980-01-01	0.965569972991943
1981-01-01	0.972760021686554
1983-01-01	0.982219994068146
1984-01-01	0.992820024490356
1985-01-01	0.986710011959076
1986-01-01	0.984969973564148
1987-01-01	0.985909998416901
1988-01-01	0.987410008907318
1993-01-01	0.987580001354218
1994-01-01	0.992730021476746
1995-01-01	0.993139982223511
1996-01-01	0.992510020732880
1997-01-01	0.992370009422302
1998-01-01	0.996749997138977
1999-01-01	0.999149978160858
2000-01-01	0.995350003242493
2001-01-01	1.000159978866580
2002-01-01	0.998920023441315
2003-01-01	0.998489975929260
2004-01-01	0.997129976749420
2005-01-01	0.995869994163513
2006-01-01	0.994340002536774
2007-01-01	0.997020006179810
2009-01-01	1.013829946517940
2010-01-01	1.002179980278020
2011-01-01	0.998499989509583
2012-01-01	1.001119971275330
2013-01-01	1.005599975585940
2014-01-01	1.003200054168700
2015-01-01	1.002539992332460
2016-01-01	1.004439949989320
2017-01-01	1.009089946746830