Year	Percent
1999-01-01	23.875
2000-01-01	24.375
2001-01-01	24.125
2002-01-01	24.550
2003-01-01	24.900
2004-01-01	23.850
2005-01-01	24.050
2006-01-01	23.050
2007-01-01	23.600
2008-01-01	23.025
2009-01-01	23.175
2010-01-01	23.975
2011-01-01	23.850
2012-01-01	24.200
2013-01-01	24.375
2014-01-01	24.975
2015-01-01	24.725
2016-01-01	22.800
2017-01-01	23.900