Year	Percent
1999-01-01	15.750
2000-01-01	16.650
2001-01-01	15.450
2002-01-01	17.525
2003-01-01	18.650
2004-01-01	21.075
2005-01-01	22.100
2006-01-01	23.225
2007-01-01	26.000
2008-01-01	26.325
2009-01-01	27.750
2010-01-01	29.250
2011-01-01	31.600
2012-01-01	33.125
2013-01-01	35.850
2014-01-01	36.950
2015-01-01	39.250
2016-01-01	40.175
2017-01-01	42.750