Year	Percent
1975-12-31	11
1976-12-31	11.1137
1977-12-31	8.8772
1978-12-31	9.1059
1979-12-31	13.6863
1980-12-31	16.3091
1981-12-31	13.2684
1982-12-31	11.898
1983-12-31	9.8175
1984-12-31	9.7018
1985-12-31	12.2359
1986-12-31	10.8829
1987-12-31	9.7297
1988-12-31	10.1186
1989-12-31	13.8492
1990-12-31	14.7668
1991-12-31	11.6838
1992-12-31	9.56
1993-12-31	6.0099
1994-12-31	5.4613
1995-12-31	6.6949
1996-12-31	5.9574
1997-12-31	6.5689
1998-12-31	7.2352
1999-12-31	5.3398
2000-12-31	5.9653
2001-12-31	5.1235
2002-12-31	4
2003-12-31	3.6937
2004-12-31	4.3848
2005-12-31	4.6468
2006-12-31	4.6379
2007-12-31	5.5128
2008-12-31	4.6821
2009-12-31	0.6423
2010-12-31	0.5
2011-12-31	0.5
2012-12-31	0.5
2013-12-31	0.5
2014-12-31	0.5