Year	Percent
2001-01-01	59.450
2002-01-01	59.200
2003-01-01	58.700
2004-01-01	58.050
2005-01-01	58.175
2006-01-01	58.875
2007-01-01	59.775
2008-01-01	59.950
2009-01-01	58.025
2010-01-01	57.825
2011-01-01	58.725
2012-01-01	58.800
2013-01-01	59.100
2014-01-01	59.575
2015-01-01	60.025
2016-01-01	60.425
2017-01-01	61.175