Year	Ratio
1978-01-01	0.111699998378754
1988-01-01	0.151879996061325
1989-01-01	0.153050005435944
1990-01-01	0.133389994502068
1991-01-01	0.170410007238388
1992-01-01	0.178580000996590
1993-01-01	0.178360000252724
1994-01-01	0.212650001049042
1995-01-01	0.210859999060631
1996-01-01	0.217199996113777
1997-01-01	0.186969995498657
1998-01-01	0.200399994850159
1999-01-01	0.216519996523857
2001-01-01	0.208250001072884
2002-01-01	0.278620004653931
2003-01-01	0.281639993190765
2004-01-01	0.320369988679886
2005-01-01	0.336059987545013
2006-01-01	0.356330007314682
2008-01-01	0.406089991331100
2009-01-01	0.404729992151260
2010-01-01	0.405979990959167
2011-01-01	0.416049987077713
2012-01-01	0.428739994764328
2013-01-01	0.443549990653992
2015-01-01	0.502510011196136
2016-01-01	0.506950020790100