Year	Percent
1998-01-01	41.400
1999-01-01	41.225
2000-01-01	40.875
2001-01-01	40.450
2002-01-01	41.250
2003-01-01	42.800
2004-01-01	42.100
2005-01-01	42.700
2006-01-01	43.675
2007-01-01	45.025
2008-01-01	45.300
2009-01-01	46.600
2010-01-01	47.600
2011-01-01	48.225
2012-01-01	50.400
2013-01-01	52.775
2014-01-01	56.500
2015-01-01	59.250
2016-01-01	61.675
2017-01-01	62.800