Year	Percent
1999-01-01	56.600
2000-01-01	56.600
2001-01-01	57.650
2002-01-01	56.775
2003-01-01	56.375
2004-01-01	55.525
2005-01-01	54.325
2006-01-01	54.175
2007-01-01	53.450
2008-01-01	53.075
2009-01-01	53.050
2010-01-01	52.300
2011-01-01	52.950
2012-01-01	52.900
2013-01-01	52.250
2014-01-01	51.925
2015-01-01	52.000
2016-01-01	52.200
2017-01-01	51.275