Year	Percent
1996-12-31	6.18
1997-12-31	6.6274
1998-12-31	7.0711
1999-12-31	5.1386
2000-12-31	5.8869
2001-12-31	4.8297
2002-12-31	3.8818
2003-12-31	3.5646
2004-12-31	4.4589
2005-12-31	4.5987
2006-12-31	4.6832
2007-12-31	5.6132
2008-12-31	4.529
2009-12-31	0.5897
2010-12-31	0.5296
2011-12-31	0.556
2012-12-31	0.4486
2013-12-31	0.4462
2014-12-31	0.4626
2015-12-31	0.5415
2016-12-31	0.4439
2017-12-31	0.3306