Year	Ratio
1970-01-01	0.97044
1971-01-01	0.97057
1972-01-01	0.97221
1973-01-01	0.97586
1974-01-01	0.97501
1975-01-01	0.97639
1976-01-01	0.97766
1977-01-01	0.97964
1978-01-01	0.98050
1979-01-01	0.98144
1980-01-01	0.98146
1981-01-01	0.98193
1982-01-01	0.98369
1983-01-01	0.98483
1984-01-01	0.98230
1985-01-01	0.98364
1986-01-01	0.98441
1987-01-01	0.98532
1988-01-01	0.98579
1989-01-01	0.98824
1990-01-01	0.98797
1991-01-01	0.98944
1992-01-01	0.99680
1993-01-01	0.98925
1994-01-01	0.98948
1995-01-01	0.99182
1996-01-01	0.99090
1997-01-01	0.98523
1998-01-01	0.98279
1999-01-01	0.98363
2000-01-01	0.98654
2001-01-01	0.98718
2002-01-01	0.98804
2003-01-01	0.98871
2004-01-01	0.99000
2005-01-01	0.98990
2006-01-01	0.99104
2007-01-01	0.99102
2008-01-01	0.98956
2009-01-01	0.99070
2010-01-01	0.99176
2011-01-01	0.99316
2012-01-01	0.99629
2013-01-01	0.99577
2014-01-01	0.99608
2015-01-01	0.99998
2016-01-01	1.00169