Year	Ratio
1975-01-01	0.72413
1976-01-01	0.72217
1977-01-01	0.74180
1978-01-01	0.77289
1979-01-01	0.76896
1980-01-01	0.75515
1981-01-01	0.72816
1982-01-01	0.72195
1983-01-01	0.73550
1984-01-01	0.74239
1985-01-01	0.75511
1986-01-01	0.75333
1987-01-01	0.77800
1988-01-01	0.78323
1989-01-01	0.79390
1990-01-01	0.79513
1991-01-01	0.80242
1992-01-01	0.82003
1993-01-01	0.82825
1994-01-01	0.86351
1995-01-01	0.87973
1996-01-01	0.89377
1997-01-01	0.90058
1998-01-01	0.91765
1999-01-01	0.93489
2000-01-01	0.94269
2001-01-01	0.94716
2002-01-01	0.95161
2003-01-01	0.95591
2004-01-01	0.96926
2005-01-01	0.98251
2006-01-01	0.99464
2007-01-01	1.00180
2008-01-01	1.00850
2009-01-01	1.01725
2010-01-01	0.99932
2011-01-01	1.00272
2012-01-01	1.01001
2013-01-01	1.00775
2014-01-01	1.01455
2015-01-01	1.01472
2016-01-01	1.01640