Year	Percent
1999-01-01	56.300
2000-01-01	52.550
2001-01-01	51.375
2002-01-01	51.675
2003-01-01	51.125
2004-01-01	50.750
2005-01-01	51.625
2006-01-01	52.250
2007-01-01	53.825
2008-01-01	54.450
2009-01-01	53.150
2010-01-01	52.750
2011-01-01	53.900
2012-01-01	53.675
2013-01-01	53.075
2014-01-01	52.050
2015-01-01	51.375
2016-01-01	51.000
2017-01-01	50.575