Year	Percent
1999-01-01	16.850
2000-01-01	18.025
2001-01-01	18.775
2002-01-01	20.125
2003-01-01	21.725
2004-01-01	18.800
2005-01-01	22.450
2006-01-01	25.150
2007-01-01	27.450
2008-01-01	30.075
2009-01-01	31.075
2010-01-01	33.600
2011-01-01	33.000
2012-01-01	34.500
2013-01-01	36.375
2014-01-01	37.475
2015-01-01	40.175
2016-01-01	42.725
2017-01-01	44.425