Year	Percent
1999-01-01	23.150
2000-01-01	20.575
2001-01-01	15.275
2002-01-01	16.225
2003-01-01	15.900
2004-01-01	14.875
2005-01-01	12.025
2006-01-01	11.400
2007-01-01	10.750
2008-01-01	12.850
2009-01-01	18.200
2010-01-01	20.325
2011-01-01	21.925
2012-01-01	25.175
2013-01-01	26.800
2014-01-01	25.550
2015-01-01	23.650
2016-01-01	21.525
2017-01-01	19.125