Year	Ratio
1970-01-01	0.71508
1971-01-01	0.71660
1972-01-01	0.72043
1973-01-01	0.72105
1974-01-01	0.71872
1975-01-01	0.72642
1976-01-01	0.73417
1977-01-01	0.74201
1978-01-01	0.74376
1979-01-01	0.75376
1980-01-01	0.75843
1981-01-01	0.76730
1982-01-01	0.77263
1983-01-01	0.77379
1984-01-01	0.78069
1985-01-01	0.79112
1986-01-01	0.79923
1987-01-01	0.80609
1988-01-01	0.81050
1989-01-01	0.81013
1990-01-01	0.81357
1991-01-01	0.82901
1992-01-01	0.83708
1993-01-01	0.84865
1994-01-01	0.85402
1995-01-01	0.85558
1996-01-01	0.85806
1997-01-01	0.86679
1998-01-01	0.86838
1999-01-01	0.87312
2000-01-01	0.87888
2001-01-01	0.88716
2002-01-01	0.89443
2003-01-01	0.94075
2004-01-01	0.94305
2005-01-01	0.94542
2006-01-01	0.95082
2007-01-01	0.95648
2008-01-01	0.97135
2009-01-01	0.97789
2010-01-01	0.98298
2011-01-01	0.98498
2012-01-01	0.98968
2013-01-01	1.01984
2014-01-01	1.01609
2015-01-01	1.01828
2016-01-01	1.03471