Year	Percent
1999-01-01	4.42013808687732
2000-01-01	4.43234373871891
2001-01-01	4.09300275187405
2002-01-01	3.67021851274840
2003-01-01	3.91374916321824
2004-01-01	4.17588827979842
2005-01-01	4.00965041863680
2006-01-01	3.62110986414689
2007-01-01	2.68032831597624
2008-01-01	2.20507512128110
2009-01-01	3.35385481311146
2010-01-01	3.64506134015773
2011-01-01	3.33945783458431
2012-01-01	3.48871385178949
2013-01-01	3.50664542347986