Year	Ratio
1971-01-01	0.330900013446808
1972-01-01	0.330029994249344
1973-01-01	0.348930001258850
1974-01-01	0.336780011653900
1975-01-01	0.359299987554550
1976-01-01	0.355129987001419
1977-01-01	0.364230006933212
1985-01-01	0.381000012159348
1986-01-01	0.398050010204315
1987-01-01	0.398380011320114
1988-01-01	0.405629992485046
1989-01-01	0.425830006599426
1990-01-01	0.444139987230301
1991-01-01	0.455650001764297
1992-01-01	0.478109985589981
1993-01-01	0.479229986667633
1994-01-01	0.484140008687973
1995-01-01	0.487729996442795
1996-01-01	0.497110009193420
1997-01-01	0.528150022029877
1998-01-01	0.554250001907349
1999-01-01	0.588389992713928
2000-01-01	0.614880025386810
2001-01-01	0.639249980449677
2002-01-01	0.649909973144531
2003-01-01	0.665700018405914
2004-01-01	0.659269988536835
2005-01-01	0.678030014038086
2006-01-01	0.681649982929230
2007-01-01	0.700389981269836
2008-01-01	0.706839978694916
2009-01-01	0.710259974002838
2010-01-01	0.735400021076202
2011-01-01	0.753369987010956
2012-01-01	0.761900007724762
2013-01-01	0.767300009727478
2014-01-01	0.763469994068146
2015-01-01	0.775699973106384
2016-01-01	0.777580022811890