Year	Ratio
1970-01-01	0.485590010881424
1971-01-01	0.485029995441437
1972-01-01	0.504289984703064
1973-01-01	0.527190029621124
1974-01-01	0.573329985141754
1975-01-01	0.525510013103485
1976-01-01	0.480190008878708
1977-01-01	0.549539983272552
1982-01-01	0.891290009021759
1983-01-01	0.834810018539429
1984-01-01	0.916689991950989
1985-01-01	1.300690054893490
1986-01-01	1.325139999389650
1987-01-01	1.213950037956240
1990-01-01	1.069890022277830
1991-01-01	0.960319995880127
1992-01-01	0.982869982719421
1995-01-01	1.051929950714110
1997-01-01	1.122630000114440
2002-01-01	1.110589981079100