Year	Percent
1999-01-01	34.975
2000-01-01	37.025
2001-01-01	39.225
2002-01-01	39.875
2003-01-01	40.850
2004-01-01	41.225
2005-01-01	43.075
2006-01-01	44.100
2007-01-01	44.525
2008-01-01	45.475
2009-01-01	43.975
2010-01-01	43.550
2011-01-01	44.475
2012-01-01	43.875
2013-01-01	43.250
2014-01-01	44.300
2015-01-01	46.900
2016-01-01	49.075
2017-01-01	50.500