Year	Ratio
1970-01-01	0.474229991436005
1971-01-01	0.473619997501373
1972-01-01	0.481009989976883
1973-01-01	0.529999971389771
1977-01-01	0.482840001583099
1978-01-01	0.533779978752136
1979-01-01	0.516160011291504
1980-01-01	0.468970000743866
1981-01-01	0.512700021266937
1982-01-01	0.550369977951050
1983-01-01	0.414799988269806
1984-01-01	0.350010007619858
1986-01-01	0.716409981250763
1987-01-01	0.778069972991943
1989-01-01	0.786710023880005
1990-01-01	0.771619975566864
1999-01-01	0.906710028648376
2000-01-01	0.840560019016266
2001-01-01	0.832449972629547
2002-01-01	0.761690020561218
2004-01-01	0.798389971256256
2005-01-01	0.830760002136230
2006-01-01	0.815559983253479
2007-01-01	0.770389974117279
2008-01-01	0.833750009536743
2009-01-01	0.869170010089874
2010-01-01	0.873610019683838
2011-01-01	0.852999985218048
2012-01-01	0.911109983921051
2013-01-01	0.909919977188110