Year	Percent
1998-01-01	60.700
1999-01-01	58.550
2000-01-01	58.125
2001-01-01	58.425
2002-01-01	56.150
2003-01-01	55.925
2004-01-01	55.300
2005-01-01	54.000
2006-01-01	54.850
2007-01-01	53.000
2008-01-01	53.325
2009-01-01	54.025
2010-01-01	52.575
2011-01-01	53.550
2012-01-01	53.050
2013-01-01	53.150
2014-01-01	52.525
2015-01-01	50.075
2016-01-01	49.050
2017-01-01	45.375