Year	Percent
1986-01-01	63.925
1987-01-01	63.525
1988-01-01	61.075
1989-01-01	58.950
1990-01-01	58.775
1991-01-01	57.050
1992-01-01	56.600
1993-01-01	57.100
1994-01-01	58.750
1995-01-01	60.550
1996-01-01	61.475
1997-01-01	61.000
1998-01-01	60.000
1999-01-01	60.550
2000-01-01	61.200
2001-01-01	62.200
2002-01-01	63.000
2003-01-01	63.150
2004-01-01	64.200
2005-01-01	65.075
2006-01-01	65.550
2007-01-01	65.925
2008-01-01	65.550
2009-01-01	64.000
2010-01-01	63.525
2011-01-01	63.875
2012-01-01	63.300
2013-01-01	63.900
2014-01-01	64.975
2015-01-01	65.025
2016-01-01	66.225
2017-01-01	67.350