Year	Percent
1998-01-01	41.100
1999-01-01	41.525
2000-01-01	38.200
2001-01-01	35.600
2002-01-01	34.900
2003-01-01	36.250
2004-01-01	35.575
2005-01-01	34.225
2006-01-01	34.275
2007-01-01	31.700
2008-01-01	28.350
2009-01-01	33.300
2010-01-01	40.300
2011-01-01	51.525
2012-01-01	63.075
2013-01-01	63.825
2014-01-01	58.125
2015-01-01	54.975
2016-01-01	50.775
2017-01-01	48.150