Year	Percent
1998-01-01	47.250
1999-01-01	42.325
2000-01-01	39.250
2001-01-01	37.100
2002-01-01	35.250
2003-01-01	32.300
2004-01-01	30.125
2005-01-01	31.350
2006-01-01	31.450
2007-01-01	32.825
2008-01-01	32.375
2009-01-01	31.075
2010-01-01	29.575
2011-01-01	29.025
2012-01-01	29.225
2013-01-01	29.925
2014-01-01	32.325
2015-01-01	33.150
2016-01-01	33.750
2017-01-01	33.800