Year	Percent
1998-01-01	51.14010000000000
1999-01-01	53.59070000000000
2000-01-01	51.50000000000000
2001-01-01	49.50000000000000
2002-01-01	51.56870000000000
2003-01-01	55.23820000000000
2004-01-01	57.47380000000000
2005-01-01	61.42340000000000
2006-01-01	61.42340000000000
2007-01-01	65.33800000000001
2008-01-01	60.03590000000000
2009-01-01	57.64180000000000
2010-01-01	57.28450000000000
2011-01-01	58.16870000000000
2012-01-01	59.00120000000000
2013-01-01	62.45590000000000
2014-01-01	62.38980000000000
2015-01-01	64.96070000000000
2016-01-01	68.88590000000000