Year	Percent
1998-01-01	34.300
1999-01-01	40.000
2000-01-01	41.100
2001-01-01	41.800
2002-01-01	40.675
2003-01-01	39.625
2004-01-01	39.400
2005-01-01	40.500
2006-01-01	42.100
2007-01-01	44.600
2008-01-01	44.700
2009-01-01	39.600
2010-01-01	38.800
2011-01-01	40.375
2012-01-01	41.800
2013-01-01	41.525
2014-01-01	41.350
2015-01-01	40.475
2016-01-01	41.650
2017-01-01	42.525