Year	Percent
1998-01-01	31.875
1999-01-01	38.200
2000-01-01	39.925
2001-01-01	40.700
2002-01-01	40.250
2003-01-01	39.175
2004-01-01	39.450
2005-01-01	40.575
2006-01-01	41.600
2007-01-01	44.675
2008-01-01	45.025
2009-01-01	41.475
2010-01-01	39.925
2011-01-01	41.225
2012-01-01	42.650
2013-01-01	43.875
2014-01-01	42.950
2015-01-01	42.800
2016-01-01	43.250
2017-01-01	43.700