Year	Percent
1991-01-01	11.3710002899170
1992-01-01	11.3409996032715
1993-01-01	11.5270004272461
1994-01-01	11.5290002822876
1995-01-01	11.5480003356934
1996-01-01	11.4209995269775
1997-01-01	11.5069999694824
1998-01-01	11.4890003204346
1999-01-01	11.4149999618530
2000-01-01	11.3929996490479
2001-01-01	11.3269996643066
2002-01-01	11.5000000000000
2003-01-01	11.4289999008179
2004-01-01	11.3570003509521
2005-01-01	11.4110002517700
2006-01-01	11.3809995651245
2007-01-01	11.4099998474121
2008-01-01	11.3330001831055
2009-01-01	11.4399995803833
2010-01-01	11.4189996719360
2011-01-01	11.4980001449585
2012-01-01	11.4770002365112
2013-01-01	11.4270000457764
2014-01-01	11.4499998092651
2015-01-01	11.4460000991821
2016-01-01	11.3570003509521
2017-01-01	11.2510004043579