Year	Percent
1998-01-01	8.900
1999-01-01	8.200
2000-01-01	8.200
2001-01-01	7.700
2002-01-01	8.200
2003-01-01	8.400
2004-01-01	8.600
2005-01-01	8.250
2006-01-01	7.550
2007-01-01	6.575
2008-01-01	6.600
2009-01-01	8.925
2010-01-01	9.575
2011-01-01	9.550
2012-01-01	10.425
2013-01-01	10.800
2014-01-01	10.125
2015-01-01	9.350
2016-01-01	8.400
2017-01-01	7.475