Year	Percent
1998-01-01	8.789150000000000
1999-01-01	10.160700000000000
2000-01-01	14.618700000000000
2001-01-01	17.338800000000000
2002-01-01	19.459200000000000
2003-01-01	27.395800000000000
2004-01-01	26.331600000000000
2005-01-01	22.878700000000000
2006-01-01	22.346999999999998
2007-01-01	20.765000000000000
2008-01-01	20.916999999999998
2009-01-01	20.890200000000000
2010-01-01	22.254400000000000
2011-01-01	20.638600000000000
2012-01-01	20.434500000000000
2013-01-01	21.070600000000000
2014-01-01	22.526800000000000
2015-01-01	25.165000000000000
2016-01-01	29.591700000000000
2017-01-01	29.245900000000000