Year	Percent
1999-01-01	55.325
2000-01-01	55.800
2001-01-01	56.050
2002-01-01	55.900
2003-01-01	54.825
2004-01-01	57.350
2005-01-01	58.175
2006-01-01	58.725
2007-01-01	58.825
2008-01-01	59.400
2009-01-01	59.700
2010-01-01	59.375
2011-01-01	58.500
2012-01-01	58.800
2013-01-01	58.350
2014-01-01	59.075
2015-01-01	58.925
2016-01-01	59.250
2017-01-01	61.425