Year	Percent
1999-01-01	16.350
2000-01-01	17.150
2001-01-01	17.925
2002-01-01	19.275
2003-01-01	20.775
2004-01-01	18.175
2005-01-01	21.800
2006-01-01	24.550
2007-01-01	26.500
2008-01-01	29.275
2009-01-01	30.325
2010-01-01	32.975
2011-01-01	32.175
2012-01-01	33.525
2013-01-01	35.225
2014-01-01	36.400
2015-01-01	38.825
2016-01-01	41.100
2017-01-01	42.800