Year	Percent
1999-01-01	36.850
2000-01-01	35.450
2001-01-01	37.750
2002-01-01	39.075
2003-01-01	41.050
2004-01-01	43.800
2005-01-01	47.750
2006-01-01	49.750
2007-01-01	52.500
2008-01-01	56.650
2009-01-01	54.925
2010-01-01	54.025
2011-01-01	52.450
2012-01-01	53.675
2013-01-01	53.275
2014-01-01	53.150
2015-01-01	53.575
2016-01-01	55.075
2017-01-01	56.625