Year	Percent
1991-01-01	60.1469993591309
1992-01-01	58.4469985961914
1993-01-01	59.0919990539551
1994-01-01	60.2500000000000
1995-01-01	60.7210006713867
1996-01-01	58.6339988708496
1997-01-01	59.6189994812012
1998-01-01	60.3180007934570
1999-01-01	58.2229995727539
2000-01-01	61.8149986267090
2001-01-01	60.5289993286133
2002-01-01	61.5180015563965
2003-01-01	60.8510017395020
2004-01-01	63.0460014343262
2005-01-01	63.7949981689453
2006-01-01	64.8580017089844
2007-01-01	65.1679992675781
2008-01-01	63.4459991455078
2009-01-01	63.1110000610352
2010-01-01	62.4039993286133
2011-01-01	62.0950012207031
2012-01-01	62.8499984741211
2013-01-01	62.3590011596680
2014-01-01	61.9049987792969
2015-01-01	64.1529998779297
2016-01-01	65.3629989624023
2017-01-01	65.6309967041016