Year	Ratio
1970-01-01	0.84559
1971-01-01	0.83254
1972-01-01	0.82372
1973-01-01	0.81675
1974-01-01	0.82657
1975-01-01	0.83213
1976-01-01	0.82118
1977-01-01	0.82006
1978-01-01	0.83564
1979-01-01	0.85287
1980-01-01	0.84629
1981-01-01	0.83392
1982-01-01	0.83866
1983-01-01	0.85088
1984-01-01	0.85697
1985-01-01	0.83957
1986-01-01	0.86232
1987-01-01	0.87633
1988-01-01	0.88044
1989-01-01	0.88949
1990-01-01	0.89318
1991-01-01	0.90226
1992-01-01	0.91144
1993-01-01	0.91789
1994-01-01	0.93897
1995-01-01	0.94892
1996-01-01	0.95584
1997-01-01	0.95997
1998-01-01	0.96818
1999-01-01	0.97423
2000-01-01	0.98111
2001-01-01	0.98127
2002-01-01	0.98293
2003-01-01	0.98737
2004-01-01	0.99733
2005-01-01	1.00905
2006-01-01	1.01621
2007-01-01	1.02504
2008-01-01	1.03078
2009-01-01	1.03649
2010-01-01	1.02016
2011-01-01	1.02140
2012-01-01	1.02292
2013-01-01	1.02877
2014-01-01	1.03071
2015-01-01	1.02438
2016-01-01	1.02279