Year	Percent
1998-01-01	50.1188216477238
1999-01-01	49.7190581287453
2000-01-01	50.0672484450543
2001-01-01	49.9190212895203
2002-01-01	50.2196104716550
2003-01-01	50.8060964539698
2004-01-01	50.6913722971991
2005-01-01	50.9512568173611
2006-01-01	51.3459033142996
2007-01-01	51.4744584072503
2008-01-01	51.5549335683190
2009-01-01	50.3979286285571
2010-01-01	48.3379847141533
2011-01-01	44.5918784070405
2012-01-01	40.6049046703037
2013-01-01	38.8645278541844