Year	Percent
1998-01-01	33.850
1999-01-01	37.850
2000-01-01	40.475
2001-01-01	44.925
2002-01-01	47.250
2003-01-01	48.275
2004-01-01	50.425
2005-01-01	52.675
2006-01-01	54.275
2007-01-01	55.000
2008-01-01	55.850
2009-01-01	56.275
2010-01-01	56.850
2011-01-01	57.175
2012-01-01	59.700
2013-01-01	60.500
2014-01-01	61.400
2015-01-01	62.475
2016-01-01	62.950
2017-01-01	63.400