Year	Percent
1999-01-01	47.450
2000-01-01	49.575
2001-01-01	50.900
2002-01-01	52.075
2003-01-01	53.325
2004-01-01	54.550
2005-01-01	56.700
2006-01-01	58.250
2007-01-01	59.175
2008-01-01	58.050
2009-01-01	54.000
2010-01-01	52.900
2011-01-01	52.100
2012-01-01	49.975
2013-01-01	48.900
2014-01-01	49.550
2015-01-01	51.075
2016-01-01	52.500
2017-01-01	53.700