Year	Percent
1999-01-01	18.100
2000-01-01	18.650
2001-01-01	20.400
2002-01-01	18.550
2003-01-01	19.775
2004-01-01	19.275
2005-01-01	17.725
2006-01-01	16.825
2007-01-01	11.275
2008-01-01	11.425
2009-01-01	13.425
2010-01-01	13.850
2011-01-01	16.775
2012-01-01	20.900
2013-01-01	23.800
2014-01-01	21.350
2015-01-01	14.825
2016-01-01	14.750
2017-01-01	12.825