Year	Ratio
1971-01-01	0.429879993200302
1972-01-01	0.482910007238388
1973-01-01	0.529100000858307
1974-01-01	0.551180005073547
1975-01-01	0.593540012836456
1976-01-01	0.624189972877502
1977-01-01	0.645659983158112
1978-01-01	0.682640016078949
1979-01-01	0.707899987697601
1980-01-01	0.731840014457703
1981-01-01	0.750140011310577
1982-01-01	0.775399982929230
1983-01-01	0.807579994201660
1984-01-01	0.821349978446960
1985-01-01	0.842239975929260
1986-01-01	0.861570000648499
1987-01-01	0.864329993724823
1988-01-01	0.875750005245209
1989-01-01	0.873809993267059
1990-01-01	0.881720006465912
1991-01-01	0.872259974479675
1992-01-01	0.887730002403259
1993-01-01	0.900089979171753
1994-01-01	0.916639983654022
1995-01-01	0.942870020866394
1996-01-01	0.965560019016266
1997-01-01	0.982339978218079
1998-01-01	1.002799987792970
2014-01-01	1.193330049514770
2015-01-01	1.193609952926640
2016-01-01	1.188109993934630