Year	Percent
1999-01-01	60.300
2000-01-01	60.100
2001-01-01	60.525
2002-01-01	60.100
2003-01-01	59.800
2004-01-01	60.650
2005-01-01	60.400
2006-01-01	60.925
2007-01-01	60.650
2008-01-01	60.950
2009-01-01	60.625
2010-01-01	59.775
2011-01-01	59.600
2012-01-01	59.075
2013-01-01	58.575
2014-01-01	58.025
2015-01-01	57.800
2016-01-01	59.450
2017-01-01	58.250