Year	Percent
1998-01-01	48.575
1999-01-01	49.525
2000-01-01	50.300
2001-01-01	50.850
2002-01-01	50.925
2003-01-01	50.650
2004-01-01	50.350
2005-01-01	50.550
2006-01-01	50.600
2007-01-01	50.625
2008-01-01	50.950
2009-01-01	50.025
2010-01-01	49.225
2011-01-01	47.500
2012-01-01	46.250
2013-01-01	45.275
2014-01-01	46.125
2015-01-01	46.925
2016-01-01	47.525
2017-01-01	49.050