Year	Ratio
1971-01-01	0.248469993472099
1972-01-01	0.301899999380112
1973-01-01	0.344929993152618
1976-01-01	0.546750009059906
1979-01-01	0.814429998397827
1980-01-01	0.719160020351410
1981-01-01	0.765690028667450
1982-01-01	0.807869970798492
1983-01-01	0.700139999389648
1984-01-01	0.917289972305298
1985-01-01	0.943340003490448
1986-01-01	0.881990015506744
1988-01-01	0.744270026683807
1990-01-01	0.711499989032745
1994-01-01	0.797930002212524
1995-01-01	0.888390004634857
1996-01-01	0.867269992828369
1997-01-01	0.985880017280579
2004-01-01	1.909770011901860
2005-01-01	2.141190052032470
2006-01-01	2.268379926681520
2007-01-01	2.172820091247560
2008-01-01	1.429290056228640
2009-01-01	2.052710056304930
2010-01-01	2.421789884567260
2011-01-01	2.280669927597050
2012-01-01	2.054620027542110