Year	Percent
1999-01-01	21.975
2000-01-01	22.750
2001-01-01	25.475
2002-01-01	24.450
2003-01-01	23.475
2004-01-01	29.000
2005-01-01	30.700
2006-01-01	32.575
2007-01-01	33.450
2008-01-01	32.775
2009-01-01	35.575
2010-01-01	35.050
2011-01-01	31.200
2012-01-01	32.900
2013-01-01	33.500
2014-01-01	35.425
2015-01-01	36.600
2016-01-01	38.550
2017-01-01	42.750