Year	Percent
1998-01-01	63.175
1999-01-01	63.775
2000-01-01	63.825
2001-01-01	63.300
2002-01-01	64.150
2003-01-01	64.950
2004-01-01	66.175
2005-01-01	66.350
2006-01-01	66.650
2007-01-01	66.550
2008-01-01	66.625
2009-01-01	67.450
2010-01-01	67.825
2011-01-01	67.250
2012-01-01	67.450
2013-01-01	67.475
2014-01-01	67.425
2015-01-01	67.825
2016-01-01	68.200
2017-01-01	68.250