Year	Ratio
1971-01-01	0.569379985332489
1972-01-01	0.568989992141724
1973-01-01	0.627229988574982
1974-01-01	0.587819993495941
1975-01-01	0.583050012588501
1976-01-01	0.569379985332489
1977-01-01	0.582449972629547
1978-01-01	0.576210021972656
1979-01-01	0.584439992904663
1980-01-01	0.578519999980927
1981-01-01	0.580619990825653
1982-01-01	0.593900024890900
1983-01-01	0.594489991664886
1984-01-01	0.593970000743866
1985-01-01	0.608290016651154
1986-01-01	0.610440015792847
1987-01-01	0.608489990234375
1988-01-01	0.608619987964630
1989-01-01	0.611530005931854
1990-01-01	0.602739989757538
1991-01-01	0.601989984512329
1992-01-01	0.602360010147095
1993-01-01	0.619180023670197
1994-01-01	0.639180004596710
1995-01-01	0.686720013618469
1996-01-01	0.668420016765594
1997-01-01	0.666779994964600
1998-01-01	0.704710006713867
1999-01-01	0.715480029582977
2000-01-01	0.745389997959137
2001-01-01	0.733349978923798
2002-01-01	0.752979993820190
2003-01-01	0.762650012969971
2004-01-01	0.775990009307861
2005-01-01	0.785449981689453
2006-01-01	0.805320024490356
2007-01-01	0.819060027599335
2008-01-01	0.833959996700287
2009-01-01	0.844850003719330
2010-01-01	0.857580006122589
2011-01-01	0.870090007781982
2012-01-01	0.874549984931946
2014-01-01	0.887210011482239
2015-01-01	0.897539973258972
2016-01-01	0.882719993591309