Year	Percent
1999-01-01	47.225
2000-01-01	48.025
2001-01-01	48.225
2002-01-01	49.175
2003-01-01	49.925
2004-01-01	50.400
2005-01-01	52.550
2006-01-01	52.200
2007-01-01	52.150
2008-01-01	51.475
2009-01-01	48.200
2010-01-01	44.975
2011-01-01	42.550
2012-01-01	40.350
2013-01-01	39.575
2014-01-01	37.325
2015-01-01	36.175
2016-01-01	34.750
2017-01-01	35.100