Year	Ratio
1970-01-01	0.90217
1971-01-01	0.89483
1972-01-01	0.88925
1973-01-01	0.89799
1974-01-01	0.90832
1975-01-01	0.91221
1976-01-01	0.92443
1977-01-01	0.92978
1978-01-01	0.93406
1979-01-01	0.93770
1980-01-01	0.95225
1981-01-01	0.94604
1982-01-01	0.93952
1983-01-01	0.93722
1984-01-01	0.93149
1985-01-01	0.94054
1986-01-01	0.94542
1987-01-01	0.95653
1988-01-01	0.96737
1989-01-01	0.97944
1990-01-01	0.99081
1991-01-01	0.99808
1992-01-01	1.00415
1993-01-01	1.00136
1994-01-01	1.00778
1995-01-01	0.99681
1996-01-01	1.00182
1997-01-01	0.99706
1998-01-01	0.99446
1999-01-01	0.98131
2000-01-01	0.98064
2001-01-01	0.97992
2002-01-01	0.98353
2003-01-01	0.98222
2004-01-01	0.97164
2005-01-01	0.97431
2006-01-01	0.98961
2007-01-01	0.99860
2008-01-01	1.00950
2009-01-01	1.01229
2010-01-01	1.00929
2011-01-01	1.00402
2012-01-01	1.01844
2013-01-01	1.02157
2014-01-01	1.02091
2015-01-01	1.01652
2016-01-01	1.01576