Year	Ratio
1970-01-01	0.996360003948212
1971-01-01	0.989390015602112
1972-01-01	0.985480010509491
1973-01-01	0.987190008163452
1974-01-01	0.980960011482239
1975-01-01	0.977869987487793
1976-01-01	0.981019973754883
1977-01-01	0.978380024433136
1978-01-01	0.975950002670288
1979-01-01	0.972850024700165
1980-01-01	0.970730006694794
1981-01-01	0.972159981727600
1982-01-01	0.960210025310516
1983-01-01	0.967459976673126
1984-01-01	0.964969992637634
1985-01-01	0.965789973735809
1986-01-01	0.964410006999969
1989-01-01	0.978359997272491
1990-01-01	0.980199992656708
1991-01-01	0.979560017585754
1992-01-01	0.975109994411469
1993-01-01	0.977919995784760
1996-01-01	0.970319986343384
1997-01-01	0.972459971904755
1998-01-01	0.971029996871948
1999-01-01	0.971419990062714
2000-01-01	0.975080013275146
2002-01-01	0.975279986858368
2003-01-01	0.974089980125427
2004-01-01	0.953289985656738
2005-01-01	0.954540014266968
2006-01-01	0.954559981822968
2007-01-01	0.950250029563904
2008-01-01	0.947889983654022
2009-01-01	0.951210021972656
2010-01-01	0.971059978008270
2011-01-01	0.968500018119812
2012-01-01	0.969020009040833
2013-01-01	0.969720005989075
2014-01-01	0.970510005950928
2015-01-01	0.971059978008270
2016-01-01	0.972519993782043