Year	Percent
1999-01-01	39.8790382234606
2000-01-01	40.6859233093285
2001-01-01	41.0190599379949
2002-01-01	40.7603392486719
2003-01-01	39.9308809136581
2004-01-01	42.1670673988984
2005-01-01	42.4882717705260
2006-01-01	42.8075759390758
2007-01-01	43.5194349326225
2008-01-01	44.1657901971991
2009-01-01	43.7128020080670
2010-01-01	42.8172590127015
2011-01-01	41.4940736341074
2012-01-01	40.8163265306122
2013-01-01	39.5614409419949
2014-01-01	40.1341088252259