Year	Percent
1998-01-01	42.475
1999-01-01	49.075
2000-01-01	51.000
2001-01-01	50.850
2002-01-01	50.875
2003-01-01	49.975
2004-01-01	48.900
2005-01-01	50.425
2006-01-01	51.025
2007-01-01	53.575
2008-01-01	53.525
2009-01-01	51.175
2010-01-01	49.325
2011-01-01	50.500
2012-01-01	52.025
2013-01-01	52.875
2014-01-01	52.600
2015-01-01	53.275
2016-01-01	53.125
2017-01-01	54.175