Year	Percent
1998-01-01	48.700
1999-01-01	48.800
2000-01-01	48.500
2001-01-01	47.550
2002-01-01	47.100
2003-01-01	51.050
2004-01-01	52.700
2005-01-01	53.975
2006-01-01	54.475
2007-01-01	55.325
2008-01-01	56.400
2009-01-01	59.900
2010-01-01	62.025
2011-01-01	59.600
2012-01-01	60.775
2013-01-01	63.775
2014-01-01	65.250
2015-01-01	65.775
2016-01-01	64.975
2017-01-01	64.450