Year	Percent
1998-01-01	14.225
1999-01-01	15.650
2000-01-01	15.100
2001-01-01	14.450
2002-01-01	14.100
2003-01-01	13.600
2004-01-01	14.825
2005-01-01	14.325
2006-01-01	12.550
2007-01-01	12.025
2008-01-01	10.875
2009-01-01	12.400
2010-01-01	15.550
2011-01-01	20.625
2012-01-01	27.150
2013-01-01	30.850
2014-01-01	29.775
2015-01-01	28.700
2016-01-01	28.050
2017-01-01	25.625