Year	Ratio
1970-01-01	0.94207
1971-01-01	0.95493
1972-01-01	0.93492
1973-01-01	0.91717
1974-01-01	0.91103
1975-01-01	0.91999
1976-01-01	0.90185
1977-01-01	0.92665
1978-01-01	0.94591
1979-01-01	0.96720
1980-01-01	0.99383
1981-01-01	1.03182
1982-01-01	1.03173
1983-01-01	1.04109
1984-01-01	1.03435
1985-01-01	1.06510
1986-01-01	1.10245
1987-01-01	1.12957
1988-01-01	1.14535
1989-01-01	1.14674
1990-01-01	1.18555
1991-01-01	1.20803
1992-01-01	1.18640
1993-01-01	1.20738
1994-01-01	1.26688
1995-01-01	1.35726
1996-01-01	1.42038
1997-01-01	1.49404
1998-01-01	1.58712
1999-01-01	1.68367
2000-01-01	1.80025
2001-01-01	1.88082
2002-01-01	1.96485
2003-01-01	1.99947
2004-01-01	1.91126
2005-01-01	1.91944
2006-01-01	1.96154
2007-01-01	1.95992
2008-01-01	1.93723
2009-01-01	2.00881
2010-01-01	2.02522
2011-01-01	2.01980
2012-01-01	1.89579
2013-01-01	1.99700
2014-01-01	1.85589
2015-01-01	1.72402
2016-01-01	1.73785