Year	Percent
1991-01-01	9.44900035858154
1992-01-01	9.46000003814697
1993-01-01	9.47999954223633
1994-01-01	9.53699970245361
1995-01-01	9.54100036621094
1996-01-01	9.56299972534180
1997-01-01	9.54199981689453
1998-01-01	9.44299983978271
1999-01-01	9.49499988555908
2000-01-01	9.52299976348877
2001-01-01	9.48499965667725
2002-01-01	9.37699985504150
2003-01-01	8.98999977111816
2004-01-01	9.15900039672852
2005-01-01	9.33399963378906
2006-01-01	10.10499954223630
2007-01-01	8.83899974822998
2008-01-01	9.99600028991699
2009-01-01	10.34300041198730
2010-01-01	9.94799995422363
2011-01-01	9.67399978637695
2012-01-01	9.51000022888184
2013-01-01	9.29300022125244
2014-01-01	9.56000041961670
2015-01-01	8.53299999237061
2016-01-01	7.67100000381470
2017-01-01	6.77400016784668