Year	Percent
1998-01-01	51.9
1999-01-01	50.5
2000-01-01	42.5
2001-01-01	79.6
2002-01-01	66.8
2003-01-01	77.5
2004-01-01	80.9
2005-01-01	112.9
2006-01-01	112.9
2007-01-01	112.9
2008-01-01	112.9
2009-01-01	70.9
2010-01-01	70
2011-01-01	60.9
2012-01-01	60.2
2013-01-01	59.8
2014-01-01	45.7
2015-01-01	41.8