Year	Percent
1999-01-01	47.650
2000-01-01	48.525
2001-01-01	47.925
2002-01-01	47.875
2003-01-01	47.575
2004-01-01	48.125
2005-01-01	48.825
2006-01-01	48.725
2007-01-01	49.600
2008-01-01	49.950
2009-01-01	49.225
2010-01-01	49.575
2011-01-01	49.375
2012-01-01	49.225
2013-01-01	49.050
2014-01-01	48.950
2015-01-01	48.800
2016-01-01	48.950
2017-01-01	50.025