Year	Ratio
1971-01-01	0.450700014829636
1973-01-01	0.372379988431931
1976-01-01	1.065670013427730
1977-01-01	0.553520023822784
1978-01-01	0.518280029296875
1979-01-01	0.487390011548996
1986-01-01	0.618669986724854
1987-01-01	0.685609996318817
1989-01-01	0.750190019607544
1990-01-01	0.767970025539398
1991-01-01	0.810109972953796
1994-01-01	0.773320019245148
1995-01-01	0.830910027027130
1996-01-01	0.813099980354309
1997-01-01	0.817269980907440
1998-01-01	0.835640013217926
1999-01-01	0.844619989395142
2000-01-01	0.867269992828369
2001-01-01	0.839760005474091
2002-01-01	0.834739983081818
2003-01-01	0.834619998931885
2004-01-01	0.902170002460480
2005-01-01	0.891260027885437
2006-01-01	0.872349977493286
2007-01-01	0.886669993400574
2008-01-01	0.893710017204285
2009-01-01	0.903349995613098
2010-01-01	0.911639988422394
2011-01-01	0.927219986915588
2012-01-01	0.917089998722076
2013-01-01	0.937300026416779
2014-01-01	0.917869985103607
2015-01-01	0.904150009155273