Year	Percent
1998-01-01	1.26
1999-01-01	2.77
2000-01-01	4.23
2001-01-01	5.43
2002-01-01	7.59
2003-01-01	8.53
2004-01-01	8.93
2005-01-01	8.48
2006-01-01	8.91
2007-01-01	9.40
2008-01-01	8.85
2009-01-01	10.94
2010-01-01	10.35
2011-01-01	9.39
2012-01-01	10.26
2013-01-01	10.37
2014-01-01	11.38
2015-01-01	14.26
2016-01-01	14.61