Year	Percent
1999-01-01	47.175
2000-01-01	47.100
2001-01-01	47.675
2002-01-01	48.575
2003-01-01	48.950
2004-01-01	47.400
2005-01-01	48.300
2006-01-01	49.075
2007-01-01	50.050
2008-01-01	51.025
2009-01-01	51.300
2010-01-01	51.650
2011-01-01	52.000
2012-01-01	52.350
2013-01-01	52.350
2014-01-01	52.325
2015-01-01	52.400
2016-01-01	52.825
2017-01-01	53.100