Year	Ratio
1970-01-01	0.76592
1971-01-01	0.76595
1972-01-01	0.76611
1973-01-01	0.76496
1974-01-01	0.76287
1975-01-01	0.80057
1976-01-01	0.82198
1977-01-01	0.82803
1978-01-01	0.82703
1979-01-01	0.82811
1980-01-01	0.83052
1981-01-01	0.83211
1982-01-01	0.82872
1983-01-01	0.82608
1984-01-01	0.83118
1985-01-01	0.83778
1986-01-01	0.85328
1987-01-01	0.85889
1988-01-01	0.86389
1989-01-01	0.86563
1990-01-01	0.87122
1991-01-01	0.88105
1992-01-01	0.88841
1993-01-01	0.89498
1994-01-01	0.89942
1995-01-01	0.90396
1996-01-01	0.90761
1997-01-01	0.91385
1998-01-01	0.91675
1999-01-01	0.92039
2000-01-01	0.92326
2001-01-01	0.92897
2002-01-01	0.93179
2003-01-01	0.95754
2004-01-01	0.96057
2005-01-01	0.96071
2006-01-01	0.96288
2007-01-01	0.96553
2008-01-01	0.97323
2009-01-01	0.97773
2010-01-01	0.98005
2011-01-01	0.98189
2012-01-01	0.98697
2013-01-01	1.00738
2014-01-01	1.00705
2015-01-01	1.00795
2016-01-01	1.01839