Year	Ratio
1970-01-01	0.80091
1971-01-01	0.92680
1972-01-01	0.73175
1973-01-01	0.72963
1974-01-01	0.60395
1975-01-01	0.58602
1976-01-01	0.60014
1977-01-01	0.61943
1978-01-01	0.62565
1979-01-01	0.57608
1980-01-01	0.61060
1981-01-01	0.51457
1982-01-01	0.76154
1983-01-01	0.85133
1984-01-01	0.88233
1985-01-01	0.87986
1986-01-01	0.85374
1987-01-01	0.85154
1988-01-01	0.85256
1989-01-01	0.85568
1990-01-01	0.82676
1991-01-01	0.81868
1992-01-01	0.83731
1993-01-01	0.85773
1994-01-01	0.88000
1995-01-01	0.90446
1996-01-01	0.92953
1997-01-01	0.95462
1998-01-01	0.98156
1999-01-01	1.01751
2000-01-01	1.05297
2001-01-01	1.07059
2002-01-01	1.09805
2003-01-01	1.13191
2004-01-01	1.12468
2005-01-01	1.11974
2006-01-01	1.11554