Year	Percent
1999-01-01	64.975
2000-01-01	66.675
2001-01-01	70.125
2002-01-01	70.700
2003-01-01	72.700
2004-01-01	75.650
2005-01-01	76.225
2006-01-01	76.850
2007-01-01	78.200
2008-01-01	78.525
2009-01-01	78.525
2010-01-01	78.025
2011-01-01	78.575
2012-01-01	76.625
2013-01-01	76.350
2014-01-01	74.125
2015-01-01	72.500
2016-01-01	71.775
2017-01-01	71.800