Year	Ratio
1972-01-01	0.949010014533997
1973-01-01	0.956560015678406
1974-01-01	0.953350007534027
1989-01-01	0.979300022125244
1990-01-01	0.980719983577728
1991-01-01	0.984470009803772
1992-01-01	0.980090022087097
1993-01-01	0.985629975795746
1994-01-01	0.987190008163452
1995-01-01	0.991100013256073
1996-01-01	0.991620004177094
1997-01-01	0.979900002479553
1998-01-01	0.976559996604919
1999-01-01	0.981679975986481
2000-01-01	0.985689997673035
2001-01-01	0.989319980144501
2002-01-01	0.991479992866516
2003-01-01	0.993979990482330
2004-01-01	0.994419991970062
2005-01-01	0.994379997253418
2006-01-01	0.994560003280640
2007-01-01	0.993659973144531
2008-01-01	0.991590023040771
2009-01-01	0.990980029106140
2010-01-01	0.992320001125336
2011-01-01	0.996060013771057
2012-01-01	1.002449989318850
2013-01-01	1.002429962158200
2014-01-01	1.002099990844730
2015-01-01	1.007820010185240
2016-01-01	1.009649991989140