Year	Ratio
1971-01-01	0.854080021381378
1972-01-01	0.856109976768494
1973-01-01	0.865029990673065
1974-01-01	0.859709978103638
1975-01-01	0.880200028419495
1976-01-01	0.766919970512390
1977-01-01	0.822730004787445
1978-01-01	0.901579976081848
1979-01-01	0.886950016021729
1980-01-01	0.912419974803925
1981-01-01	0.957939982414246
1982-01-01	0.959450006484985
1983-01-01	0.879199981689453
1985-01-01	0.933690011501312
1988-01-01	0.948639988899231
1989-01-01	0.952939987182617
1990-01-01	0.959940016269684
1991-01-01	0.976769983768463
1992-01-01	0.915340006351471
1993-01-01	0.955550014972687
1994-01-01	0.965860009193420
1995-01-01	1.037619948387150
1996-01-01	0.961489975452423
1998-01-01	0.961860001087189
1999-01-01	0.965510010719299
2000-01-01	0.960770010948181
2001-01-01	0.961399972438812
2002-01-01	0.961080014705658
2003-01-01	0.957809984683990
2004-01-01	0.958029985427856
2005-01-01	0.956690013408661
2006-01-01	0.961419999599457
2007-01-01	0.967779994010925
2008-01-01	0.971059978008270
2009-01-01	0.977580010890961
2010-01-01	0.981909990310669
2011-01-01	0.981270015239716
2012-01-01	0.987190008163452
2013-01-01	0.992529988288879
2014-01-01	0.997259974479675
2015-01-01	0.999729990959167
2016-01-01	1.001780033111570