Year	Percent
1991-01-01	12.7510004043579
1992-01-01	12.8509998321533
1993-01-01	12.8999996185303
1994-01-01	12.8380002975464
1995-01-01	12.9250001907349
1996-01-01	12.9329996109009
1997-01-01	12.9189996719360
1998-01-01	13.0120000839233
1999-01-01	13.0100002288818
2000-01-01	12.9879999160767
2001-01-01	12.9809999465942
2002-01-01	12.8559999465942
2003-01-01	12.9770002365112
2004-01-01	12.9670000076294
2005-01-01	12.8319997787476
2006-01-01	12.8479995727539
2007-01-01	12.8800001144409
2008-01-01	12.9069995880127
2009-01-01	12.9149999618530
2010-01-01	12.9099998474121
2011-01-01	12.7729997634888
2012-01-01	12.8769998550415
2013-01-01	12.8649997711182
2014-01-01	12.8039999008179
2015-01-01	12.8640003204346
2016-01-01	12.8830003738403
2017-01-01	12.8920001983643