Year	Percent
1999-01-01	30.550
2000-01-01	29.800
2001-01-01	30.175
2002-01-01	29.175
2003-01-01	28.250
2004-01-01	27.825
2005-01-01	26.975
2006-01-01	26.450
2007-01-01	26.100
2008-01-01	25.850
2009-01-01	26.550
2010-01-01	26.825
2011-01-01	27.250
2012-01-01	27.650
2013-01-01	28.325
2014-01-01	29.075
2015-01-01	29.150
2016-01-01	29.525
2017-01-01	29.950