Year	Ratio
1971-01-01	0.230820000171661
1972-01-01	0.225419998168945
1973-01-01	0.232910007238388
1974-01-01	0.244739994406700
1976-01-01	0.308019995689392
1977-01-01	0.288729995489120
1978-01-01	0.310629993677139
1979-01-01	0.320320010185242
1980-01-01	0.359310001134872
1981-01-01	0.502179980278015
1982-01-01	0.520380020141602
1983-01-01	0.532959997653961
1984-01-01	0.561909973621368
1985-01-01	0.554210007190704
1986-01-01	0.547919988632202
2007-01-01	0.460000008344650