Year	Ratio
1970-01-01	0.60143
1971-01-01	0.60709
1972-01-01	0.60895
1973-01-01	0.60537
1974-01-01	0.60519
1975-01-01	0.60681
1976-01-01	0.60977
1977-01-01	0.62340
1978-01-01	0.62686
1979-01-01	0.64015
1980-01-01	0.63799
1981-01-01	0.64018
1982-01-01	0.66279
1983-01-01	0.64835
1984-01-01	0.64175
1985-01-01	0.65756
1986-01-01	0.64851
1987-01-01	0.64341
1988-01-01	0.68116
1989-01-01	0.68875
1990-01-01	0.69614
1991-01-01	0.71524
1992-01-01	0.72376
1993-01-01	0.73395
1994-01-01	0.73681
1995-01-01	0.74284
1996-01-01	0.73964
1997-01-01	0.75353
1998-01-01	0.77012
1999-01-01	0.79397
2000-01-01	0.79880
2001-01-01	0.79738
2002-01-01	0.83031
2003-01-01	0.81690
2004-01-01	0.81187
2005-01-01	0.83662
2006-01-01	0.86501
2007-01-01	0.84816
2008-01-01	0.84634
2009-01-01	0.84908
2010-01-01	0.85066
2011-01-01	0.86282
2012-01-01	0.92673
2013-01-01	0.96819
2014-01-01	0.99917
2015-01-01	0.99424
2016-01-01	1.00925