Year	Percent
1998-01-01	52.6
1999-01-01	51.8
2000-01-01	47.8
2001-01-01	52.9
2002-01-01	54.7
2003-01-01	54.9
2004-01-01	59.3
2005-01-01	67.1
2006-01-01	71.2
2007-01-01	75.2
2008-01-01	75.3
2009-01-01	74.1
2010-01-01	70.1
2011-01-01	68.7
2012-01-01	67.8
2013-01-01	64
2014-01-01	65.0