Year	Percent
1999-01-01	39.025
2000-01-01	39.525
2001-01-01	39.250
2002-01-01	39.300
2003-01-01	40.150
2004-01-01	39.900
2005-01-01	39.850
2006-01-01	39.950
2007-01-01	39.650
2008-01-01	39.300
2009-01-01	38.675
2010-01-01	39.125
2011-01-01	39.150
2012-01-01	40.175
2013-01-01	40.550
2014-01-01	42.800
2015-01-01	44.025
2016-01-01	45.600
2017-01-01	46.150