Year	Ratio
1970-01-01	0.65342
1971-01-01	0.65522
1972-01-01	0.66717
1973-01-01	0.70127
1974-01-01	0.72518
1975-01-01	0.74833
1976-01-01	0.75460
1977-01-01	0.79429
1978-01-01	0.81682
1979-01-01	0.83782
1980-01-01	0.85518
1981-01-01	0.87399
1982-01-01	0.88458
1983-01-01	0.89127
1984-01-01	0.90103
1985-01-01	0.91464
1986-01-01	0.92649
1987-01-01	0.94304
1988-01-01	0.96427
1989-01-01	0.98424
1990-01-01	1.02039
1991-01-01	1.02868
1992-01-01	1.05375
1993-01-01	1.06122
1994-01-01	1.06928
1995-01-01	1.08926
1996-01-01	1.09784
1997-01-01	1.11309
1998-01-01	1.11879
1999-01-01	1.12343
2000-01-01	1.12715
2001-01-01	1.13579
2002-01-01	1.16130
2003-01-01	1.17511
2004-01-01	1.19117
2005-01-01	1.20025
2006-01-01	1.20870
2007-01-01	1.21273
2008-01-01	1.21671
2009-01-01	1.22432
2010-01-01	1.23072
2011-01-01	1.23154
2012-01-01	1.23308
2013-01-01	1.22032