Year	Ratio
1973-01-01	0.591769993305206
1974-01-01	0.894020020961761
1975-01-01	0.912100017070770
1976-01-01	0.821020007133484
1977-01-01	0.927119970321655
1978-01-01	1.037230014801030
1979-01-01	0.986859977245331
1980-01-01	0.955780029296875
1981-01-01	0.898570001125336
1982-01-01	0.958029985427856
1983-01-01	0.943780004978180
1984-01-01	0.922810018062592
1985-01-01	0.933059990406036
1986-01-01	0.952870011329651
1987-01-01	1.079939961433410
1988-01-01	1.152680039405820
1989-01-01	1.187860012054440
1990-01-01	1.192149996757510
1991-01-01	1.168879985809330
1992-01-01	1.156469941139220
1993-01-01	1.126389980316160
1994-01-01	1.087049961090090
1995-01-01	1.053830027580260
1997-01-01	1.102769970893860
1998-01-01	1.122380018234250
2016-01-01	0.942719995975494