Year	Percent
1999-01-01	15.925
2000-01-01	15.975
2001-01-01	15.600
2002-01-01	16.350
2003-01-01	16.250
2004-01-01	15.275
2005-01-01	15.550
2006-01-01	14.550
2007-01-01	14.650
2008-01-01	13.625
2009-01-01	13.525
2010-01-01	14.750
2011-01-01	15.275
2012-01-01	15.150
2013-01-01	15.175
2014-01-01	16.225
2015-01-01	16.600
2016-01-01	16.175
2017-01-01	17.325