Year	Percent
2003-01-01	78.625
2004-01-01	77.800
2005-01-01	79.275
2006-01-01	80.125
2007-01-01	80.775
2008-01-01	79.500
2009-01-01	74.550
2010-01-01	74.300
2011-01-01	74.200
2012-01-01	75.075
2013-01-01	76.350
2014-01-01	78.125
2015-01-01	79.700
2016-01-01	81.300
2017-01-01	80.600