Year	Ratio
1970-01-01	0.66956
1971-01-01	0.66824
1972-01-01	0.67970
1973-01-01	0.71337
1974-01-01	0.73649
1975-01-01	0.75949
1976-01-01	0.76545
1977-01-01	0.80608
1978-01-01	0.82947
1979-01-01	0.85215
1980-01-01	0.87106
1981-01-01	0.89168
1982-01-01	0.90323
1983-01-01	0.91198
1984-01-01	0.92178
1985-01-01	0.93493
1986-01-01	0.94650
1987-01-01	0.96264
1988-01-01	0.98274
1989-01-01	1.00143
1990-01-01	1.03565
1991-01-01	1.04332
1992-01-01	1.06504
1993-01-01	1.07039
1994-01-01	1.07574
1995-01-01	1.09364
1996-01-01	1.10119
1997-01-01	1.11430
1998-01-01	1.12098
1999-01-01	1.12556
2000-01-01	1.13029
2001-01-01	1.13998
2002-01-01	1.16848
2003-01-01	1.18646
2004-01-01	1.20523
2005-01-01	1.21519
2006-01-01	1.22422
2007-01-01	1.23006
2008-01-01	1.23497
2009-01-01	1.24203
2010-01-01	1.24545
2011-01-01	1.24256
2012-01-01	1.24285
2013-01-01	1.23024
2014-01-01	1.22531
2015-01-01	1.22600
2016-01-01	1.22397