Year	Ratio
1971-01-01	0.445789992809296
1972-01-01	0.454230010509491
1973-01-01	0.457109987735748
1974-01-01	0.448449999094009
1975-01-01	0.441240012645721
1976-01-01	0.460130006074905
1977-01-01	0.453319996595383
1978-01-01	0.469330012798309
1979-01-01	0.471689999103546
1980-01-01	0.509400010108948
1981-01-01	0.473780006170273
1982-01-01	0.478139996528625
1983-01-01	0.483859986066818
1984-01-01	0.497830003499985
1985-01-01	0.500140011310577
1986-01-01	0.506190001964569
1987-01-01	0.508960008621216
1988-01-01	0.511730015277863
1989-01-01	0.514429986476898
1990-01-01	0.517300009727478
1991-01-01	0.503430008888245
1992-01-01	0.511409997940063
1993-01-01	0.522909998893738
1994-01-01	0.550589978694916
1995-01-01	0.565819978713989
1996-01-01	0.583639979362488
1997-01-01	0.604210019111633
1998-01-01	0.634790003299713
1999-01-01	0.659870028495789
2000-01-01	0.685660004615784
2001-01-01	0.697329998016357
2002-01-01	0.718450009822845
2003-01-01	0.736899971961975
2004-01-01	0.766409993171692
2005-01-01	0.791209995746613
2006-01-01	0.819700002670288
2008-01-01	0.858399987220764
2009-01-01	0.876020014286041
2010-01-01	0.891640007495880
2011-01-01	0.894900023937225
2012-01-01	0.907230019569397
2013-01-01	0.915210008621216
2014-01-01	0.924269974231720
2015-01-01	0.930230021476746