Year	Ratio
1981-01-01	0.757420003414154
1986-01-01	0.889819979667664
1991-01-01	0.662500023841858
1992-01-01	0.642949998378754
1993-01-01	0.702970027923584
1994-01-01	0.779659986495972
1995-01-01	0.877009987831116
1996-01-01	0.947120010852814
1997-01-01	0.950860023498535
2006-01-01	1.047060012817380
2007-01-01	1.019539952278140
2008-01-01	0.981429994106293
2009-01-01	0.986810028553009
2010-01-01	0.989369988441467
2011-01-01	1.016289949417110
2012-01-01	1.047690033912660
2013-01-01	1.112849950790410
2014-01-01	1.141950011253360
2015-01-01	1.162340044975280
2016-01-01	1.188009977340700