Year	Percent
1991-01-01	54.9990005493164
1992-01-01	56.0559997558594
1993-01-01	57.0480003356934
1994-01-01	57.8499984741211
1995-01-01	58.3149986267090
1996-01-01	56.9529991149902
1997-01-01	55.4939994812012
1998-01-01	54.2480010986328
1999-01-01	53.3940010070801
2000-01-01	52.7430000305176
2001-01-01	52.5320014953613
2002-01-01	52.6549987792969
2003-01-01	52.9990005493164
2004-01-01	53.3250007629395
2005-01-01	53.6910018920898
2006-01-01	54.1710014343262
2007-01-01	55.0480003356934
2008-01-01	56.1959991455078
2009-01-01	57.6889991760254
2010-01-01	59.4029998779297
2011-01-01	61.0610008239746
2012-01-01	62.6609992980957
2013-01-01	64.3440017700195
2014-01-01	65.9629974365234
2015-01-01	67.2900009155273
2016-01-01	67.5569992065430
2017-01-01	67.9020004272461