Year	Ratio
1970-01-01	0.45686
1971-01-01	0.45725
1972-01-01	0.47441
1973-01-01	0.48516
1974-01-01	0.49283
1975-01-01	0.49909
1976-01-01	0.51255
1977-01-01	0.50249
1978-01-01	0.50762
1979-01-01	0.52975
1980-01-01	0.54078
1981-01-01	0.55308
1982-01-01	0.55309
1983-01-01	0.56042
1984-01-01	0.56518
1985-01-01	0.57917
1986-01-01	0.56985
1987-01-01	0.57427
1988-01-01	0.61863
1989-01-01	0.64014
1990-01-01	0.66740
1991-01-01	0.69106
1992-01-01	0.69686
1993-01-01	0.71442
1994-01-01	0.71666
1995-01-01	0.72745
1996-01-01	0.73643
1997-01-01	0.76385
1998-01-01	0.80052
1999-01-01	0.83512
2000-01-01	0.86661
2001-01-01	0.89791
2002-01-01	0.93162
2003-01-01	0.98320
2004-01-01	0.97860
2005-01-01	0.99550
2006-01-01	1.02345
2007-01-01	1.01055
2008-01-01	1.08208
2009-01-01	1.05296
2010-01-01	1.03342
2011-01-01	1.04402
2012-01-01	1.04229
2013-01-01	1.02242
2014-01-01	1.01721
2015-01-01	1.01946
2016-01-01	1.04953