Year	Percent
1999-01-01	67.300
2000-01-01	67.475
2001-01-01	68.100
2002-01-01	67.800
2003-01-01	67.125
2004-01-01	69.775
2005-01-01	70.650
2006-01-01	70.875
2007-01-01	71.300
2008-01-01	71.800
2009-01-01	71.850
2010-01-01	71.500
2011-01-01	70.275
2012-01-01	70.400
2013-01-01	70.525
2014-01-01	70.875
2015-01-01	71.750
2016-01-01	71.650
2017-01-01	74.225