Year	Percent
1999-01-01	19.375
2000-01-01	22.175
2001-01-01	23.475
2002-01-01	25.600
2003-01-01	28.950
2004-01-01	31.050
2005-01-01	33.000
2006-01-01	33.175
2007-01-01	32.225
2008-01-01	30.900
2009-01-01	31.900
2010-01-01	33.575
2011-01-01	35.250
2012-01-01	36.150
2013-01-01	37.900
2014-01-01	41.750
2015-01-01	45.300
2016-01-01	49.850
2017-01-01	51.675