Year	Percent
1998-01-01	6.67715047006114
1999-01-01	5.85471778552934
2000-01-01	5.22355261258602
2001-01-01	4.54663136759762
2002-01-01	4.28343885123396
2003-01-01	4.16104577529702
2004-01-01	4.16911247563232
2005-01-01	4.07551515770628
2006-01-01	3.85281936247206
2007-01-01	3.45404778917199
2008-01-01	3.22066476175012
2009-01-01	3.62258873401944
2010-01-01	3.60118345555471
2011-01-01	3.33772815388854
2012-01-01	3.32668299195998
2013-01-01	3.51567849304008