Year	Ratio
1970-01-01	0.81064
1971-01-01	0.80995
1972-01-01	0.81199
1973-01-01	0.83728
1974-01-01	0.85884
1975-01-01	0.88753
1976-01-01	0.91023
1977-01-01	0.94082
1978-01-01	0.96888
1979-01-01	0.97121
1980-01-01	0.97951
1981-01-01	0.99382
1982-01-01	0.98983
1983-01-01	0.99193
1984-01-01	0.99043
1985-01-01	0.98659
1986-01-01	0.99245
1987-01-01	0.99333
1988-01-01	0.98944
1989-01-01	0.98631
1990-01-01	0.98505
1991-01-01	0.98908
1992-01-01	0.98693
1993-01-01	0.98497
1994-01-01	0.98118
1995-01-01	0.98681
1996-01-01	0.98613
1997-01-01	0.98991
1998-01-01	0.99476
1999-01-01	0.99270
2000-01-01	0.99309
2001-01-01	0.99354
2002-01-01	0.98781
2003-01-01	0.99308
2004-01-01	1.00120
2005-01-01	1.00491
2006-01-01	0.99914
2007-01-01	1.00189
2008-01-01	1.00133
2009-01-01	1.00452
2010-01-01	1.00135
2011-01-01	0.99787
2012-01-01	0.99931
2013-01-01	1.00237
2014-01-01	1.00486
2015-01-01	1.00571
2016-01-01	1.00814