Year	Percent
1999-01-01	92.300
2000-01-01	91.725
2001-01-01	91.325
2002-01-01	91.900
2003-01-01	91.750
2004-01-01	91.550
2005-01-01	91.700
2006-01-01	92.300
2007-01-01	92.350
2008-01-01	93.275
2009-01-01	92.150
2010-01-01	92.025
2011-01-01	91.550
2012-01-01	90.650
2013-01-01	90.150
2014-01-01	90.300
2015-01-01	90.800
2016-01-01	90.800
2017-01-01	89.600