Year	Ratio
1971-01-01	0.0876900032162666
1975-01-01	0.1431400030851360
1976-01-01	0.2164999991655350
1977-01-01	0.2374799996614460
1978-01-01	0.2366800010204320
1981-01-01	0.2340199947357180
1982-01-01	0.2719500064849850
1983-01-01	0.2768499851226810
1985-01-01	0.3418799936771390
1986-01-01	0.1666799932718280
1987-01-01	0.1570300012826920
1988-01-01	0.1315200030803680
1989-01-01	0.1128000020980830
1990-01-01	0.0896399989724159
1991-01-01	0.0693299993872643
1992-01-01	0.0680000036954880
1993-01-01	0.0742999985814095
1994-01-01	0.0670699998736382
1996-01-01	0.0959099978208542
1997-01-01	0.1204100027680400
1998-01-01	0.1330199986696240
2004-01-01	0.1869000047445300
2005-01-01	0.2313899993896480
2006-01-01	0.2745000123977660
2007-01-01	0.2915399968624120
2008-01-01	0.3271299898624420
2009-01-01	0.3363600075244900
2010-01-01	0.3304199874401090
2011-01-01	0.3539899885654450
2012-01-01	0.3697200119495390
2013-01-01	0.4389699995517730
2014-01-01	0.4472599923610690