Year	Percent
1999-01-01	60.700
2000-01-01	61.800
2001-01-01	61.275
2002-01-01	60.775
2003-01-01	59.925
2004-01-01	60.475
2005-01-01	61.000
2006-01-01	60.825
2007-01-01	61.725
2008-01-01	61.700
2009-01-01	60.500
2010-01-01	60.650
2011-01-01	60.300
2012-01-01	59.975
2013-01-01	59.375
2014-01-01	58.800
2015-01-01	58.425
2016-01-01	58.975
2017-01-01	59.775