Year	Percent
1998-01-01	58
1999-01-01	55.8
2000-01-01	61.4
2001-01-01	63.7
2002-01-01	63.7
2003-01-01	74
2004-01-01	84.2
2005-01-01	85.9
2006-01-01	106.5
2007-01-01	132.4
2008-01-01	153.7
2009-01-01	165.7
2010-01-01	214.1
2011-01-01	269.1
2012-01-01	256.5
2013-01-01	253.3
2014-01-01	262.8
2015-01-01	243.3