Year	Percent
1999-01-01	47.700
2000-01-01	47.275
2001-01-01	47.625
2002-01-01	47.275
2003-01-01	46.075
2004-01-01	46.025
2005-01-01	44.925
2006-01-01	44.500
2007-01-01	45.050
2008-01-01	45.275
2009-01-01	45.025
2010-01-01	43.750
2011-01-01	43.425
2012-01-01	41.950
2013-01-01	41.425
2014-01-01	39.275
2015-01-01	37.800
2016-01-01	36.525
2017-01-01	35.750