Year	Percent
1999-01-01	52.300
2000-01-01	52.725
2001-01-01	52.375
2002-01-01	52.725
2003-01-01	53.925
2004-01-01	53.975
2005-01-01	55.075
2006-01-01	55.500
2007-01-01	54.950
2008-01-01	54.725
2009-01-01	54.975
2010-01-01	56.250
2011-01-01	56.575
2012-01-01	58.050
2013-01-01	58.575
2014-01-01	60.725
2015-01-01	62.200
2016-01-01	63.475
2017-01-01	64.250