Year	Percent
1999-01-01	30.350
2000-01-01	32.475
2001-01-01	33.825
2002-01-01	35.400
2003-01-01	36.900
2004-01-01	38.475
2005-01-01	40.925
2006-01-01	42.475
2007-01-01	43.700
2008-01-01	43.900
2009-01-01	42.125
2010-01-01	41.600
2011-01-01	41.275
2012-01-01	40.050
2013-01-01	39.125
2014-01-01	39.575
2015-01-01	40.600
2016-01-01	41.725
2017-01-01	42.600