Year	Percent
1998-01-01	47.850
1999-01-01	47.650
2000-01-01	47.825
2001-01-01	48.575
2002-01-01	48.225
2003-01-01	47.750
2004-01-01	47.150
2005-01-01	47.125
2006-01-01	46.900
2007-01-01	47.075
2008-01-01	47.025
2009-01-01	46.575
2010-01-01	46.500
2011-01-01	47.325
2012-01-01	47.675
2013-01-01	47.950
2014-01-01	48.175
2015-01-01	48.000
2016-01-01	47.875
2017-01-01	47.900