Year	Percent
1999-01-01	58.025
2000-01-01	59.525
2001-01-01	60.500
2002-01-01	60.675
2003-01-01	61.275
2004-01-01	61.775
2005-01-01	63.250
2006-01-01	64.050
2007-01-01	64.150
2008-01-01	61.800
2009-01-01	55.850
2010-01-01	54.150
2011-01-01	52.750
2012-01-01	50.025
2013-01-01	48.800
2014-01-01	49.700
2015-01-01	51.375
2016-01-01	52.625
2017-01-01	53.900