Year	Ratio
1970-01-01	0.43274
1971-01-01	0.43325
1972-01-01	0.44991
1973-01-01	0.45885
1974-01-01	0.46716
1975-01-01	0.47548
1976-01-01	0.48842
1977-01-01	0.47694
1978-01-01	0.48430
1979-01-01	0.50392
1980-01-01	0.51465
1981-01-01	0.52365
1982-01-01	0.52892
1983-01-01	0.53468
1984-01-01	0.53688
1985-01-01	0.54989
1986-01-01	0.53796
1987-01-01	0.53994
1988-01-01	0.58163
1989-01-01	0.59895
1990-01-01	0.62228
1991-01-01	0.64316
1992-01-01	0.65606
1993-01-01	0.66776
1994-01-01	0.67543
1995-01-01	0.68512
1996-01-01	0.69617
1997-01-01	0.72491
1998-01-01	0.75164
1999-01-01	0.78008
2000-01-01	0.81041
2001-01-01	0.84840
2002-01-01	0.87915
2003-01-01	0.92508
2004-01-01	0.91767
2005-01-01	0.93923
2006-01-01	0.97330
2007-01-01	0.96191
2008-01-01	1.03792
2009-01-01	1.00372
2010-01-01	0.98891
2011-01-01	1.00661
2012-01-01	1.00873
2013-01-01	0.99053
2014-01-01	0.98164
2015-01-01	0.98251
2016-01-01	1.01839