Year	Percent
1999-01-01	35.025
2000-01-01	33.325
2001-01-01	29.875
2002-01-01	29.300
2003-01-01	27.300
2004-01-01	24.350
2005-01-01	23.775
2006-01-01	23.150
2007-01-01	21.800
2008-01-01	21.475
2009-01-01	21.475
2010-01-01	21.975
2011-01-01	21.425
2012-01-01	23.375
2013-01-01	23.650
2014-01-01	25.875
2015-01-01	27.500
2016-01-01	28.225
2017-01-01	28.200