Year	Ratio
1970-01-01	0.45580
1971-01-01	0.45312
1972-01-01	0.44917
1973-01-01	0.45127
1974-01-01	0.45622
1975-01-01	0.45648
1976-01-01	0.46229
1977-01-01	0.43610
1978-01-01	0.43102
1979-01-01	0.43067
1980-01-01	0.45430
1981-01-01	0.44443
1982-01-01	0.47367
1983-01-01	0.49652
1984-01-01	0.52327
1985-01-01	0.52370
1986-01-01	0.55087
1987-01-01	0.55400
1988-01-01	0.56754
1989-01-01	0.58038
1990-01-01	0.58244
1991-01-01	0.59963
1992-01-01	0.61842
1993-01-01	0.63285
1994-01-01	0.64302
1995-01-01	0.68488
1996-01-01	0.70566
1997-01-01	0.72725
1998-01-01	0.74994
1999-01-01	0.76769
2000-01-01	0.78755
2001-01-01	0.79288
2002-01-01	0.80454
2003-01-01	0.80381
2004-01-01	0.77369
2005-01-01	0.79153
2006-01-01	0.79052
2007-01-01	0.79743
2008-01-01	0.81524
2009-01-01	0.81584
2010-01-01	0.84049
2011-01-01	0.86016
2012-01-01	0.86978
2013-01-01	0.87426
2014-01-01	0.88460
2015-01-01	0.89886
2016-01-01	0.89866