Year	Ratio
1981-01-01	0.991400003433228
1986-01-01	1.005460023880000
1991-01-01	0.931400001049042
1992-01-01	0.944270014762878
1993-01-01	0.945299983024597
1994-01-01	0.917609989643097
1995-01-01	0.971989989280701
1996-01-01	0.974820017814636
1997-01-01	0.968240022659302
1998-01-01	0.978479981422424
1999-01-01	0.978089988231659
2000-01-01	0.988669991493225
2001-01-01	0.985350012779236
2002-01-01	0.987820029258728
2003-01-01	0.989289999008179
2004-01-01	0.992370009422302
2005-01-01	0.995850026607513
2006-01-01	0.990390002727509
2007-01-01	0.988929986953735
2008-01-01	0.979650020599365
2009-01-01	0.981959998607636
2010-01-01	0.988479971885681
2011-01-01	0.986169993877411
2012-01-01	0.994539976119995
2013-01-01	0.994499981403351
2014-01-01	1.000200033187870
2015-01-01	1.003329992294310
2016-01-01	0.998870015144348