Year	Ratio
1971-01-01	0.791760027408600
1972-01-01	0.817239999771118
1973-01-01	0.832480013370514
1974-01-01	0.835640013217926
1975-01-01	0.862909972667694
1976-01-01	0.879800021648407
1977-01-01	0.893019974231720
1978-01-01	0.920239984989166
1979-01-01	0.928080022335052
1980-01-01	0.932479977607727
1981-01-01	0.943199992179871
1982-01-01	0.947740018367767
1983-01-01	0.957740008831024
1984-01-01	0.948610007762909
1985-01-01	0.958180010318756
1986-01-01	0.957759976387024
1987-01-01	0.911549985408783
1988-01-01	0.959649980068207
1989-01-01	0.938549995422363
1990-01-01	0.938970029354095
1991-01-01	0.918160021305084
1992-01-01	0.941209971904755
1993-01-01	0.936860024929047
1994-01-01	0.936280012130737
1995-01-01	0.854849994182587
1996-01-01	0.938589990139008
1997-01-01	0.897819995880127
1998-01-01	0.897310018539429
1999-01-01	0.962610006332397
2000-01-01	0.924839973449707
2001-01-01	0.942080020904541
2002-01-01	0.943979978561401
2003-01-01	0.939209997653961
2004-01-01	0.937510013580322
2005-01-01	0.929489970207214
2006-01-01	0.904370009899139
2007-01-01	0.931770026683807
2008-01-01	0.931469976902008
2009-01-01	0.931240022182465
2010-01-01	0.944369971752167
2011-01-01	0.942359983921051
2012-01-01	1.071920037269590