Year	Ratio
1971-01-01	0.719099998474121
1973-01-01	0.729539990425110
1974-01-01	0.732349991798401
1975-01-01	0.751919984817505
1976-01-01	0.788460016250610
1977-01-01	0.814920008182526
1978-01-01	0.839439988136292
1990-01-01	1.041560053825380
1991-01-01	0.961929976940155
1992-01-01	0.965900003910065
1993-01-01	0.976100027561188
2001-01-01	0.977330029010773
2002-01-01	1.001350045204160
2004-01-01	1.066040039062500
2005-01-01	1.048560023307800
2006-01-01	1.061820030212400
2007-01-01	1.075649976730350
2008-01-01	1.072939991950990
2009-01-01	1.078250050544740
2010-01-01	1.071740031242370
2011-01-01	1.074360013008120
2012-01-01	1.072280049324040
2013-01-01	1.092290043830870
2014-01-01	1.053820013999940
2015-01-01	0.960550010204315