Year	Percent
1999-01-01	29.075
2000-01-01	30.475
2001-01-01	30.150
2002-01-01	30.750
2003-01-01	32.000
2004-01-01	28.325
2005-01-01	31.150
2006-01-01	34.350
2007-01-01	37.250
2008-01-01	39.725
2009-01-01	40.525
2010-01-01	42.225
2011-01-01	41.450
2012-01-01	43.100
2013-01-01	45.500
2014-01-01	46.900
2015-01-01	48.550
2016-01-01	51.725
2017-01-01	53.550