Year	Percent
1999-01-01	53.225
2000-01-01	53.750
2001-01-01	54.425
2002-01-01	53.825
2003-01-01	52.775
2004-01-01	55.250
2005-01-01	55.425
2006-01-01	55.775
2007-01-01	56.850
2008-01-01	56.900
2009-01-01	55.950
2010-01-01	54.875
2011-01-01	53.200
2012-01-01	52.475
2013-01-01	51.450
2014-01-01	52.100
2015-01-01	52.175
2016-01-01	52.075
2017-01-01	54.600