Year	Percent
2000-01-01	75.450
2001-01-01	75.275
2002-01-01	75.300
2003-01-01	75.275
2004-01-01	75.275
2005-01-01	75.375
2006-01-01	75.700
2007-01-01	75.500
2008-01-01	75.800
2009-01-01	75.650
2010-01-01	75.375
2011-01-01	75.500
2012-01-01	76.050
2013-01-01	76.425
2014-01-01	76.700
2015-01-01	76.900
2016-01-01	77.300
2017-01-01	77.575