Year	Percent
1998-01-01	29.050
1999-01-01	29.025
2000-01-01	28.925
2001-01-01	29.200
2002-01-01	30.150
2003-01-01	31.450
2004-01-01	31.875
2005-01-01	32.575
2006-01-01	33.400
2007-01-01	34.500
2008-01-01	35.425
2009-01-01	36.900
2010-01-01	37.875
2011-01-01	39.350
2012-01-01	42.525
2013-01-01	45.250
2014-01-01	48.925
2015-01-01	51.050
2016-01-01	53.400
2017-01-01	55.425