Year	Percent
1998-01-01	56.225
1999-01-01	57.250
2000-01-01	57.475
2001-01-01	59.375
2002-01-01	60.075
2003-01-01	60.750
2004-01-01	59.400
2005-01-01	61.175
2006-01-01	62.375
2007-01-01	64.000
2008-01-01	64.275
2009-01-01	66.225
2010-01-01	67.200
2011-01-01	68.800
2012-01-01	67.125
2013-01-01	69.300
2014-01-01	69.000
2015-01-01	69.525
2016-01-01	69.800
2017-01-01	70.025