Year	Ratio
1971-01-01	0.360709995031357
1972-01-01	0.452320009469986
1973-01-01	0.459969997406006
1974-01-01	0.446949988603592
1975-01-01	0.429650008678436
1976-01-01	0.421070009469986
1977-01-01	0.457619994878769
1978-01-01	0.493829995393753
1996-01-01	0.584919989109039
1999-01-01	0.787039995193481
2000-01-01	0.852829992771149
2001-01-01	0.934719979763031
2002-01-01	0.994939982891083
2003-01-01	1.059440016746520
2004-01-01	1.080129981040950
2005-01-01	1.058040022850040
2006-01-01	1.078009963035580
2007-01-01	1.112319946289060
2008-01-01	1.134459972381590
2009-01-01	1.048740029335020
2010-01-01	0.988640010356903
2011-01-01	0.998610019683838
2012-01-01	1.011229991912840
2013-01-01	0.957080006599426
2014-01-01	0.928889989852905
2015-01-01	0.887310028076172
2016-01-01	0.910480022430420