Year	Ratio
1970-01-01	0.90627
1971-01-01	0.92157
1972-01-01	0.92993
1973-01-01	0.94348
1974-01-01	0.96500
1975-01-01	0.98416
1976-01-01	0.99166
1977-01-01	0.99966
1978-01-01	1.00339
1979-01-01	1.00577
1980-01-01	0.99779
1981-01-01	0.99511
1982-01-01	0.99953
1983-01-01	1.00685
1984-01-01	1.00050
1985-01-01	1.00649
1986-01-01	1.00546
1987-01-01	1.00814
1988-01-01	1.00173
1989-01-01	0.99253
1990-01-01	0.98871
1991-01-01	0.98348
1992-01-01	1.00774
1993-01-01	1.00991
1994-01-01	1.02044
1995-01-01	1.01736
1996-01-01	1.02107
1997-01-01	1.02154
1998-01-01	1.03113
1999-01-01	1.05085
2000-01-01	1.06883
2001-01-01	1.04207
2002-01-01	1.04110
2003-01-01	1.03554
2004-01-01	1.03389
2005-01-01	1.03842
2006-01-01	1.04107
2007-01-01	1.02422
2008-01-01	1.02675
2009-01-01	1.05161
2010-01-01	1.03878
2011-01-01	1.04214
2012-01-01	1.06118
2013-01-01	1.06367