Year	Ratio
1970-01-01	0.54114
1971-01-01	0.58170
1972-01-01	0.63225
1973-01-01	0.64469
1974-01-01	0.67085
1975-01-01	0.68846
1976-01-01	0.68849
1977-01-01	0.69942
1978-01-01	0.71631
1979-01-01	0.72997
1980-01-01	0.74335
1981-01-01	0.76437
1982-01-01	0.78535
1983-01-01	0.81002
1984-01-01	0.84146
1985-01-01	0.85865
1986-01-01	0.85100
1987-01-01	0.89578
1988-01-01	0.89653
1989-01-01	0.92755
1990-01-01	0.95459
1991-01-01	0.96571
1992-01-01	0.98857
1993-01-01	1.01974
1994-01-01	1.04466
1995-01-01	1.08217
1996-01-01	1.11089
1997-01-01	1.14734
1998-01-01	1.15165
1999-01-01	1.17308
2000-01-01	1.19859
2001-01-01	1.17706
2002-01-01	1.20186
2003-01-01	1.21425
2004-01-01	1.21154
2005-01-01	1.22871
2006-01-01	1.24758
2007-01-01	1.27855
2008-01-01	1.29069
2009-01-01	1.30443
2010-01-01	1.31325
2011-01-01	1.30226
2012-01-01	1.30946
2013-01-01	1.31345
2014-01-01	1.31340
2015-01-01	1.32940
2016-01-01	1.32128