Year	Ratio
1971-01-01	0.839519977569580
1972-01-01	0.828140020370483
1973-01-01	0.822549998760223
1974-01-01	0.833840012550354
1975-01-01	0.811020016670227
1976-01-01	0.802150011062622
1977-01-01	0.802900016307831
1978-01-01	0.798740029335022
1979-01-01	0.809469997882843
1980-01-01	0.818120002746582
1981-01-01	0.826929986476898
1982-01-01	0.821600019931793
1983-01-01	0.820829987525940
1984-01-01	0.820699989795685
1985-01-01	0.801630020141602
1987-01-01	0.787490010261536
1988-01-01	0.827109992504120
1989-01-01	0.835229992866516
1990-01-01	0.844039976596832
1991-01-01	0.855210006237030
1992-01-01	0.871749997138977
1993-01-01	0.882309973239899
1994-01-01	0.888530015945435
1995-01-01	0.898370027542114
1999-01-01	0.924250006675720
2000-01-01	0.932370007038116
2001-01-01	0.941209971904755
2002-01-01	0.942809998989105
2003-01-01	0.948530018329620
2004-01-01	0.943239986896515
2005-01-01	0.961820006370544
2006-01-01	0.982420027256012
2007-01-01	0.982460021972656
2008-01-01	0.982070028781891
2009-01-01	0.981679975986481
2011-01-01	0.991159975528717
2012-01-01	0.996860027313232
2013-01-01	0.998070001602173
2014-01-01	0.999409973621368
2015-01-01	1.001170039176940
2016-01-01	1.015050053596500
2017-01-01	1.013649940490720