Year	Ratio
1979-01-01	0.94538
1980-01-01	0.94604
1981-01-01	0.94527
1982-01-01	0.94525
1983-01-01	0.94591
1984-01-01	0.94622
1985-01-01	0.94763
1986-01-01	0.94972
1987-01-01	0.94879
1988-01-01	0.94949
1989-01-01	0.95113
1990-01-01	0.95591
1991-01-01	0.95948
1992-01-01	0.96669
1993-01-01	0.97235
1994-01-01	0.97260
1995-01-01	0.96747
1996-01-01	0.96200
1997-01-01	0.95980
1998-01-01	0.95768
1999-01-01	0.95665
2000-01-01	0.96117
2001-01-01	0.96984
2002-01-01	0.97007
2003-01-01	0.97588
2004-01-01	0.98312
2005-01-01	0.98950
2006-01-01	0.99185
2007-01-01	0.99013
2008-01-01	0.99095
2009-01-01	0.99271
2010-01-01	1.00162
2011-01-01	1.00712
2012-01-01	1.01846
2013-01-01	1.01588