Year	Percent
1999-01-01	28.150
2000-01-01	28.100
2001-01-01	27.150
2002-01-01	27.500
2003-01-01	28.000
2004-01-01	25.550
2005-01-01	24.900
2006-01-01	25.100
2007-01-01	24.175
2008-01-01	24.225
2009-01-01	24.400
2010-01-01	24.625
2011-01-01	26.150
2012-01-01	26.300
2013-01-01	25.800
2014-01-01	25.625
2015-01-01	24.650
2016-01-01	25.475
2017-01-01	22.925