Year	Ratio
1971-01-01	0.982739984989166
1972-01-01	0.984350025653839
1973-01-01	0.980149984359741
1974-01-01	0.976360023021698
1975-01-01	0.972609996795654
1976-01-01	0.963680028915405
1977-01-01	0.951640009880066
1978-01-01	0.953109979629517
1979-01-01	0.929859995841980
1980-01-01	0.955179989337921
1981-01-01	0.955950021743774
1982-01-01	1.002419948577880
1983-01-01	1.002519965171810
1984-01-01	1.002550005912780
1985-01-01	0.945559978485107
1986-01-01	0.947030007839203
1987-01-01	0.945710003376007
1988-01-01	0.885969996452332
1990-01-01	0.955630004405975
1991-01-01	0.951849997043610
1992-01-01	0.961160004138947
1993-01-01	0.957080006599426
1994-01-01	0.950169980525970
1995-01-01	0.954280018806458
1996-01-01	0.951380014419556
1998-01-01	0.955770015716553
1999-01-01	0.957099974155426
2000-01-01	0.957069993019104
2001-01-01	0.983240008354187
2002-01-01	0.961449980735779
2003-01-01	0.948949992656708
2004-01-01	0.949299991130829
2005-01-01	0.952509999275208
2006-01-01	0.951040029525757
2007-01-01	0.946410000324249
2008-01-01	0.945270001888275
2009-01-01	0.966099977493286
2010-01-01	0.970130026340485
2011-01-01	0.971300005912781
2012-01-01	0.971319973468781
2013-01-01	0.964779973030090
2014-01-01	0.958259999752045
2015-01-01	0.962469995021820
2016-01-01	0.964950025081635