Year	Percent
1998-01-01	28.895
1999-01-01	32.075
2000-01-01	38.200
2001-01-01	27.100
2002-01-01	21.600
2003-01-01	22.060
2004-01-01	29.725
2005-01-01	27.480
2006-01-01	31.275
2007-01-01	32.235
2008-01-01	19.905
2009-01-01	14.365
2010-01-01	11.790
2011-01-01	11.010
2012-01-01	12.210
2013-01-01	15.275
2014-01-01	16.840
2015-01-01	15.165