Year	Ratio
1981-01-01	0.756139993667603
1986-01-01	0.818859994411469
1991-01-01	0.969210028648376
1992-01-01	0.946179986000061
1993-01-01	0.935370028018951
1994-01-01	0.943710029125214
1995-01-01	0.920459985733032
1996-01-01	0.976769983768463
1997-01-01	0.979149997234344
1999-01-01	0.994599997997284
2000-01-01	0.997770011425018
2001-01-01	1.006729960441590
2002-01-01	0.994149982929230
2003-01-01	0.987139999866486
2004-01-01	0.999819993972778
2005-01-01	0.977959990501404
2006-01-01	1.006010055541990
2008-01-01	0.961350023746490
2013-01-01	1.009189963340760
2014-01-01	1.025290012359620
2015-01-01	1.026690006256100
2016-01-01	1.021389961242680