Year	Ratio
1971-01-01	1.20442998409271
1972-01-01	1.16830003261566
1973-01-01	1.27511000633240
1974-01-01	1.59522998332977
1975-01-01	1.69879996776581
1976-01-01	1.48053002357483
1977-01-01	1.47738003730774
1978-01-01	1.47200000286102
1979-01-01	1.75984001159668
1980-01-01	1.75085997581482
1981-01-01	1.71458005905151
1982-01-01	1.45975005626678
1983-01-01	1.46326005458832
1984-01-01	1.26051998138428
1985-01-01	1.16393995285034
1986-01-01	1.18411004543304
1987-01-01	1.30168998241425
1988-01-01	1.34283995628357
1989-01-01	1.44071996212006
1990-01-01	1.90410995483398
1992-01-01	1.95991003513336
1993-01-01	1.93265998363495
1994-01-01	1.51165997982025
1995-01-01	1.57814002037048
1996-01-01	1.49661004543304
1997-01-01	1.65654003620148
1999-01-01	2.03216004371643
2001-01-01	2.22611999511719
2002-01-01	2.27552008628845
2003-01-01	2.37120008468628
2004-01-01	2.29515004158020
2013-01-01	1.85678005218506