Year	Percent
1998-01-01	30.525
1999-01-01	31.600
2000-01-01	29.200
2001-01-01	28.050
2002-01-01	26.550
2003-01-01	26.650
2004-01-01	26.500
2005-01-01	25.775
2006-01-01	24.975
2007-01-01	22.675
2008-01-01	21.875
2009-01-01	25.725
2010-01-01	33.000
2011-01-01	44.700
2012-01-01	55.300
2013-01-01	58.250
2014-01-01	52.425
2015-01-01	49.800
2016-01-01	47.350
2017-01-01	43.575