Year	Percent
1998-01-01	24.400
1999-01-01	25.550
2000-01-01	25.400
2001-01-01	23.900
2002-01-01	25.250
2003-01-01	26.475
2004-01-01	25.300
2005-01-01	27.125
2006-01-01	28.025
2007-01-01	28.200
2008-01-01	28.675
2009-01-01	29.450
2010-01-01	31.075
2011-01-01	29.875
2012-01-01	30.075
2013-01-01	30.975
2014-01-01	29.875
2015-01-01	29.525
2016-01-01	33.600
2017-01-01	34.850