Year	Ratio
1970-01-01	0.60996
1971-01-01	0.60473
1972-01-01	0.65115
1973-01-01	0.66578
1974-01-01	0.68965
1975-01-01	0.70755
1976-01-01	0.70364
1977-01-01	0.71489
1978-01-01	0.73311
1979-01-01	0.74547
1980-01-01	0.76095
1981-01-01	0.78084
1982-01-01	0.80158
1983-01-01	0.83203
1984-01-01	0.85882
1985-01-01	0.87511
1986-01-01	0.86986
1987-01-01	0.91243
1988-01-01	0.91311
1989-01-01	0.94245
1990-01-01	0.96831
1991-01-01	0.97904
1992-01-01	0.99970
1993-01-01	1.02874
1994-01-01	1.05259
1995-01-01	1.08705
1996-01-01	1.11324
1997-01-01	1.14839
1998-01-01	1.15249
1999-01-01	1.17221
2000-01-01	1.19669
2001-01-01	1.17632
2002-01-01	1.20028
2003-01-01	1.21228
2004-01-01	1.20953
2005-01-01	1.22368
2006-01-01	1.24346
2007-01-01	1.27219
2008-01-01	1.28448
2009-01-01	1.29817
2010-01-01	1.30562
2011-01-01	1.29586
2012-01-01	1.30338
2013-01-01	1.30664
2014-01-01	1.30665
2015-01-01	1.32168
2016-01-01	1.31510