Year	Percent
1999-01-01	76.100
2000-01-01	74.725
2001-01-01	74.825
2002-01-01	75.025
2003-01-01	76.025
2004-01-01	74.625
2005-01-01	75.250
2006-01-01	77.200
2007-01-01	78.025
2008-01-01	80.125
2009-01-01	77.775
2010-01-01	75.800
2011-01-01	76.500
2012-01-01	76.375
2013-01-01	76.000
2014-01-01	76.800
2015-01-01	78.150
2016-01-01	80.000
2017-01-01	80.000