Year	Ratio
1981-01-01	0.267230004072189
1987-01-01	0.415600001811981
1988-01-01	0.431840002536774
1989-01-01	0.441460013389587
1990-01-01	0.455509990453720
1991-01-01	0.480639994144440
1992-01-01	0.520139992237091
1993-01-01	0.515169978141785
1994-01-01	0.564480006694794
1995-01-01	0.579119980335236
1996-01-01	0.520900011062622
1997-01-01	0.544269979000092
1998-01-01	0.723609983921051
1999-01-01	0.721210002899170
2000-01-01	0.737990021705627
2001-01-01	0.775120019912720
2002-01-01	0.783410012722015
2003-01-01	0.825869977474213
2004-01-01	0.855199992656708
2005-01-01	0.875580012798309
2006-01-01	0.843039989471436
2008-01-01	0.880270004272461
2009-01-01	0.836409986019135
2010-01-01	0.850759983062744
2011-01-01	0.844389975070953
2012-01-01	0.844919979572296
2013-01-01	0.935959994792938
2014-01-01	0.914080023765564
2015-01-01	0.929199993610382
2016-01-01	0.971099972724915