Year	Percent
1998-01-01	57.150
1999-01-01	59.325
2000-01-01	60.175
2001-01-01	60.900
2002-01-01	60.875
2003-01-01	60.525
2004-01-01	60.400
2005-01-01	61.125
2006-01-01	62.000
2007-01-01	62.900
2008-01-01	63.575
2009-01-01	61.325
2010-01-01	60.825
2011-01-01	61.275
2012-01-01	61.250
2013-01-01	60.425
2014-01-01	60.050
2015-01-01	59.675
2016-01-01	59.850
2017-01-01	60.375