Year	Percent
1999-01-01	38.800
2000-01-01	40.875
2001-01-01	41.900
2002-01-01	43.025
2003-01-01	44.000
2004-01-01	44.450
2005-01-01	45.975
2006-01-01	46.825
2007-01-01	47.325
2008-01-01	49.100
2009-01-01	50.025
2010-01-01	50.750
2011-01-01	52.400
2012-01-01	53.500
2013-01-01	54.050
2014-01-01	55.400
2015-01-01	57.625
2016-01-01	59.200
2017-01-01	59.625