Year	Ratio
1970-01-01	0.75680
1971-01-01	0.75655
1972-01-01	0.75768
1973-01-01	0.75692
1974-01-01	0.75545
1975-01-01	0.79144
1976-01-01	0.81185
1977-01-01	0.81804
1978-01-01	0.81775
1979-01-01	0.81888
1980-01-01	0.82188
1981-01-01	0.82352
1982-01-01	0.82225
1983-01-01	0.81987
1984-01-01	0.82501
1985-01-01	0.83037
1986-01-01	0.84516
1987-01-01	0.85136
1988-01-01	0.85502
1989-01-01	0.85718
1990-01-01	0.86266
1991-01-01	0.87231
1992-01-01	0.87934
1993-01-01	0.88562
1994-01-01	0.88988
1995-01-01	0.89256
1996-01-01	0.89535
1997-01-01	0.90097
1998-01-01	0.90352
1999-01-01	0.90885
2000-01-01	0.91186
2001-01-01	0.91704
2002-01-01	0.91907
2003-01-01	0.94216
2004-01-01	0.94408
2005-01-01	0.94730
2006-01-01	0.95118
2007-01-01	0.95429
2008-01-01	0.96201
2009-01-01	0.96744
2010-01-01	0.97043
2011-01-01	0.97279
2012-01-01	0.97739
2013-01-01	0.99480
2014-01-01	0.99440
2015-01-01	0.99668
2016-01-01	1.00544