Year	Percent
1999-01-01	52.075
2000-01-01	51.450
2001-01-01	51.775
2002-01-01	51.400
2003-01-01	52.200
2004-01-01	50.875
2005-01-01	50.900
2006-01-01	51.900
2007-01-01	53.050
2008-01-01	54.625
2009-01-01	52.775
2010-01-01	52.325
2011-01-01	52.525
2012-01-01	52.700
2013-01-01	53.325
2014-01-01	54.275
2015-01-01	55.925
2016-01-01	58.325
2017-01-01	60.275