Year	Percent
1996-12-31	5.988
1997-12-31	6.5294
1998-12-31	7.0944
1999-12-31	5.1367
2000-12-31	5.8028
2001-12-31	4.8929
2002-12-31	3.8426
2003-12-31	3.5497
2004-12-31	4.3661
2005-12-31	4.6005
2006-12-31	4.6466
2007-12-31	5.5606
2008-12-31	4.6085
2009-12-31	0.5916
2010-12-31	0.522
2011-12-31	0.5281
2012-12-31	0.4543
2013-12-31	0.4463
2014-12-31	0.4545
2015-12-31	0.5176
2016-12-31	0.4279
2017-12-31	0.2981