Year	Percent
2000-01-01	75.700
2001-01-01	74.650
2002-01-01	73.875
2003-01-01	74.500
2004-01-01	74.100
2005-01-01	73.625
2006-01-01	76.250
2007-01-01	77.725
2008-01-01	78.375
2009-01-01	77.650
2010-01-01	76.825
2011-01-01	78.175
2012-01-01	78.400
2013-01-01	78.600
2014-01-01	79.300
2015-01-01	80.425
2016-01-01	81.850
2017-01-01	82.650