Year	Ratio
1970-01-01	0.731710016727448
1993-01-01	0.845589995384216
1996-01-01	1.231750011444090
1999-01-01	1.377859950065610
2000-01-01	1.363250017166140
2001-01-01	1.380139946937560
2002-01-01	1.400650024414060
2003-01-01	1.379770040512080
2004-01-01	1.342700004577640
2005-01-01	1.132300019264220
2007-01-01	1.352900028228760
2008-01-01	1.360820055007930
2009-01-01	1.443379998207090
2010-01-01	1.415779948234560