Year	Percent
1999-01-01	59.725
2000-01-01	60.050
2001-01-01	60.525
2002-01-01	60.050
2003-01-01	60.250
2004-01-01	60.125
2005-01-01	59.475
2006-01-01	59.150
2007-01-01	58.850
2008-01-01	59.325
2009-01-01	58.850
2010-01-01	59.000
2011-01-01	58.775
2012-01-01	59.200
2013-01-01	59.275
2014-01-01	59.375
2015-01-01	59.650
2016-01-01	60.050
2017-01-01	59.925