Year	Ratio
1993-01-01	0.991280019283295
1994-01-01	0.994059979915619
1995-01-01	0.993730008602142
1996-01-01	0.979460000991821
1997-01-01	0.974860012531281
1998-01-01	0.967760026454926
1999-01-01	0.972940027713776
2000-01-01	0.982010006904602
2001-01-01	0.987119972705841
2002-01-01	0.997759997844696
2003-01-01	0.984690010547638
2004-01-01	0.982110023498535
2005-01-01	0.979009985923767
2006-01-01	0.974879980087280
2007-01-01	0.977360010147095
2008-01-01	0.984849989414215
2009-01-01	0.981149971485138
2010-01-01	0.985610008239746
2012-01-01	0.986750006675720
2013-01-01	0.990079998970032
2014-01-01	0.987030029296875
2015-01-01	0.995360016822815