Year	Percent
1999-01-01	84.700
2000-01-01	85.300
2001-01-01	85.450
2002-01-01	86.625
2003-01-01	87.300
2004-01-01	85.450
2005-01-01	85.725
2006-01-01	86.125
2007-01-01	86.525
2008-01-01	86.500
2009-01-01	86.975
2010-01-01	87.150
2011-01-01	87.625
2012-01-01	88.150
2013-01-01	88.325
2014-01-01	88.000
2015-01-01	88.025
2016-01-01	88.375
2017-01-01	88.650