Year	Percent
1999-01-01	51.075
2000-01-01	51.800
2001-01-01	52.250
2002-01-01	52.075
2003-01-01	50.950
2004-01-01	53.425
2005-01-01	54.075
2006-01-01	54.500
2007-01-01	55.400
2008-01-01	56.525
2009-01-01	56.200
2010-01-01	55.200
2011-01-01	53.700
2012-01-01	53.275
2013-01-01	51.975
2014-01-01	52.800
2015-01-01	52.975
2016-01-01	54.150
2017-01-01	56.800