Year	Percent
1998-01-01	56.400
1999-01-01	56.900
2000-01-01	57.750
2001-01-01	58.500
2002-01-01	59.275
2003-01-01	59.875
2004-01-01	60.075
2005-01-01	61.025
2006-01-01	61.400
2007-01-01	62.000
2008-01-01	62.050
2009-01-01	62.100
2010-01-01	62.625
2011-01-01	61.800
2012-01-01	61.975
2013-01-01	61.650
2014-01-01	61.600
2015-01-01	61.750
2016-01-01	61.575
2017-01-01	62.300