Year	Percent
1999-01-01	9.795
2000-01-01	8.895
2001-01-01	7.780
2002-01-01	8.485
2003-01-01	10.030
2004-01-01	14.200
2005-01-01	15.320
2006-01-01	20.770
2007-01-01	19.030
2008-01-01	9.160
2009-01-01	15.170
2010-01-01	16.660
2011-01-01	13.420
2012-01-01	16.330
2013-01-01	20.770
2014-01-01	16.650
2015-01-01	19.500