Year	Percent
1997-12-31	6.5225
1998-12-31	7.2164
1999-12-31	5.2182
2000-12-31	5.8549
2001-12-31	5.0357
2002-12-31	3.9235
2003-12-31	3.6128
2004-12-31	4.3557
2005-12-31	4.6767
2006-12-31	4.673
2007-12-31	5.5848
2008-12-31	4.5932
2009-12-31	0.5483
2010-12-31	0.4881
2011-12-31	0.5259
2012-12-31	0.4659
2013-12-31	0.4283
2014-12-31	0.4259
2015-12-31	0.4559
2016-12-31	0.3601
2017-12-31	0.2514
2018-12-31	0.56
2019-12-31	0.7086