Year	Ratio
1971-01-01	0.196209996938705
1972-01-01	0.196989998221397
1973-01-01	0.186660006642342
1974-01-01	0.215350002050400
1975-01-01	0.230749994516373
1976-01-01	0.234040006995201
1977-01-01	0.255510002374649
1978-01-01	0.264780014753342
1979-01-01	0.335559993982315
1986-01-01	0.497189998626709
1987-01-01	0.521549999713898
1988-01-01	0.525110006332397
1989-01-01	0.558269977569580
1990-01-01	0.610440015792847
1991-01-01	0.585179984569550
1992-01-01	0.624289989471436
1993-01-01	0.653859972953796
1994-01-01	0.680119991302490
1995-01-01	0.707419991493225
1997-01-01	0.703700006008148
1998-01-01	0.728259980678558
1999-01-01	0.722729980945587
2000-01-01	0.731729984283447
2001-01-01	0.757870018482208
2002-01-01	0.775740027427673
2003-01-01	0.774800002574921
2004-01-01	0.830990016460419
2005-01-01	0.803340017795563
2006-01-01	0.875869989395142
2007-01-01	0.899370014667511
2008-01-01	0.946730017662048
2009-01-01	0.883170008659363
2010-01-01	0.902869999408722
2011-01-01	0.922439992427826
2012-01-01	0.924719989299774
2013-01-01	0.955370008945465
2014-01-01	0.966660022735596
2015-01-01	0.958360016345978
2016-01-01	0.926320016384125