Year	Ratio
1971-01-01	0.707270026206970
1998-01-01	0.926769971847534
1999-01-01	0.927489995956421
2000-01-01	0.918749988079071
2001-01-01	0.922710001468658
2002-01-01	0.926800012588501
2003-01-01	0.927030026912689
2004-01-01	0.931379973888397
2005-01-01	0.941280007362366
2006-01-01	0.951810002326965
2007-01-01	0.962369978427887
2008-01-01	0.971849977970123
2009-01-01	0.984120011329651
2010-01-01	0.987670004367828
2011-01-01	0.995469987392426
2012-01-01	0.994279980659485
2013-01-01	0.993030011653900
2014-01-01	0.990059971809387
2015-01-01	0.983799993991852
2016-01-01	0.980220019817352