Year	Percent
1998-01-01	46.900
1999-01-01	47.400
2000-01-01	48.100
2001-01-01	48.625
2002-01-01	47.700
2003-01-01	42.775
2004-01-01	40.875
2005-01-01	39.625
2006-01-01	38.725
2007-01-01	38.525
2008-01-01	37.675
2009-01-01	32.450
2010-01-01	29.750
2011-01-01	28.675
2012-01-01	24.775
2013-01-01	22.900
2014-01-01	22.875
2015-01-01	24.100
2016-01-01	25.500
2017-01-01	27.575