Year	Percent
1998-01-01	55.100
1999-01-01	56.175
2000-01-01	54.500
2001-01-01	54.975
2002-01-01	59.250
2003-01-01	59.925
2004-01-01	60.175
2005-01-01	62.150
2006-01-01	62.750
2007-01-01	62.475
2008-01-01	64.150
2009-01-01	63.150
2010-01-01	62.450
2011-01-01	62.600
2012-01-01	64.025
2013-01-01	66.075
2014-01-01	67.925
2015-01-01	68.275
2016-01-01	70.950
2017-01-01	73.175