Year	Ratio
1981-01-01	0.981100022792816
1982-01-01	0.988590002059937
1983-01-01	0.987060010433197
1984-01-01	0.976769983768463
1985-01-01	0.983810007572174
1986-01-01	0.976740002632141
1987-01-01	0.996540009975433
1988-01-01	0.982609987258911
1989-01-01	0.974839985370636
1990-01-01	0.970510005950928
1991-01-01	0.971650004386902
1992-01-01	0.974370002746582
1993-01-01	0.977190017700195
1994-01-01	0.976790010929108
1995-01-01	0.971979975700378
1996-01-01	0.976689994335175
1997-01-01	0.983799993991852
1998-01-01	0.983020007610321
1999-01-01	0.984730005264282
2000-01-01	0.990180015563965
2001-01-01	0.984669983386993
2002-01-01	0.982810020446777
2003-01-01	0.975849986076355
2004-01-01	0.976890027523041
2005-01-01	0.974259972572327
2006-01-01	0.975700020790100
2007-01-01	0.984480023384094
2008-01-01	0.981890022754669
2009-01-01	0.981840014457703
2010-01-01	0.984979987144470
2011-01-01	0.997280001640320
2012-01-01	0.997889995574951
2013-01-01	0.995339989662170
2014-01-01	0.995339989662170
2015-01-01	1.001250028610230