Year	Percent
1999-01-01	17.725
2000-01-01	17.600
2001-01-01	18.800
2002-01-01	18.075
2003-01-01	17.700
2004-01-01	16.625
2005-01-01	15.450
2006-01-01	15.525
2007-01-01	14.700
2008-01-01	14.300
2009-01-01	14.425
2010-01-01	13.675
2011-01-01	15.250
2012-01-01	15.000
2013-01-01	14.650
2014-01-01	14.375
2015-01-01	14.925
2016-01-01	14.875
2017-01-01	15.125