Year	Ratio
1971-01-01	0.610140025615692
1972-01-01	0.616949975490570
1976-01-01	0.764460027217865
1977-01-01	0.765820026397705
1978-01-01	0.787010014057159
1986-01-01	0.861909985542297
1987-01-01	0.870559990406036
1988-01-01	0.886900007724762
1989-01-01	0.903819978237152
1990-01-01	0.924769997596741
1991-01-01	0.958500027656555
1992-01-01	0.982810020446777
1993-01-01	0.988659977912903
1994-01-01	0.986810028553009
1999-01-01	0.979089975357056
2000-01-01	1.046200037002560
2001-01-01	0.937560021877289
2002-01-01	0.926289975643158
2003-01-01	0.929400026798248
2004-01-01	0.923669993877411
2005-01-01	0.968330025672913
2006-01-01	0.976580023765564
2007-01-01	0.999350011348724
2009-01-01	1.016160011291500
2010-01-01	1.049970030784610
2014-01-01	1.025760054588320
2017-01-01	1.098219990730290