Year	Percent
1999-01-01	46.800
2000-01-01	45.975
2001-01-01	45.525
2002-01-01	43.375
2003-01-01	41.075
2004-01-01	39.275
2005-01-01	36.675
2006-01-01	35.375
2007-01-01	34.625
2008-01-01	32.400
2009-01-01	31.425
2010-01-01	31.075
2011-01-01	30.075
2012-01-01	30.525
2013-01-01	30.775
2014-01-01	30.975
2015-01-01	31.750
2016-01-01	32.400
2017-01-01	33.175