Year	Percent
1998-01-01	64.3052
1999-01-01	69.4620
2000-01-01	79.4000
2001-01-01	76.9000
2002-01-01	77.5672
2003-01-01	78.4172
2004-01-01	74.7366
2005-01-01	71.2183
2006-01-01	69.5794
2007-01-01	61.1505
2008-01-01	50.4363
2009-01-01	52.3603
2010-01-01	61.8834
2011-01-01	61.2286
2012-01-01	68.0191
2013-01-01	68.0301
2014-01-01	75.5529
2015-01-01	69.4159
2016-01-01	68.6525