Year	Percent
1998-01-01	47.900
1999-01-01	52.850
2000-01-01	53.600
2001-01-01	53.300
2002-01-01	52.075
2003-01-01	51.350
2004-01-01	50.525
2005-01-01	50.900
2006-01-01	52.625
2007-01-01	53.225
2008-01-01	53.425
2009-01-01	49.675
2010-01-01	49.400
2011-01-01	50.475
2012-01-01	51.175
2013-01-01	50.750
2014-01-01	51.525
2015-01-01	51.050
2016-01-01	51.250
2017-01-01	52.325