Year	Ratio
1971-01-01	0.966470003128052
1974-01-01	0.964150011539459
1976-01-01	1.021559953689580
1977-01-01	0.999599993228912
1986-01-01	0.941990017890930
1987-01-01	0.949580013751984
1991-01-01	0.955330014228821
1992-01-01	0.954029977321625
1993-01-01	0.951210021972656
1994-01-01	0.951510012149811
1995-01-01	0.957289993762970
1996-01-01	0.954169988632202
1997-01-01	0.956650018692017
1999-01-01	0.960820019245148
2000-01-01	0.951430022716522
2001-01-01	0.959230005741119
2002-01-01	0.962899982929230
2003-01-01	0.972630023956299
2004-01-01	0.968410015106201
2005-01-01	0.956669986248016
2006-01-01	0.965279996395111
2007-01-01	0.978559970855713
2008-01-01	0.960900008678436
2009-01-01	0.962430000305176
2010-01-01	0.960739970207214
2011-01-01	0.956679999828339
2012-01-01	0.965990006923676
2013-01-01	0.955160021781921
2014-01-01	0.952090024948120
2015-01-01	0.952719986438751
2016-01-01	0.950640022754669