Year	Percent
1976-12-31	13.5094
1977-12-31	6.2931
1978-12-31	11.5635
1979-12-31	15.8421
1980-12-31	13.0161
1981-12-31	14.6701
1982-12-31	9.7204
1983-12-31	8.8391
1984-12-31	9.1225
1985-12-31	11.1662
1986-12-31	10.6646
1987-12-31	8.209
1988-12-31	12.5083
1989-12-31	14.479
1990-12-31	13.0581
1991-12-31	10.1879
1992-12-31	6.3574
1993-12-31	4.8934
1994-12-31	5.9162
1995-12-31	6.2159
1996-12-31	6.1647
1997-12-31	7.1058
1998-12-31	5.5552
1999-12-31	5.6154
2000-12-31	5.6113
2001-12-31	3.8333
2002-12-31	3.8427
2003-12-31	3.739
2004-12-31	4.691
2005-12-31	4.4271
2006-12-31	5.108
2007-12-31	5.2388
2008-12-31	1.242
2009-12-31	0.4911
2010-12-31	0.5007
2011-12-31	0.2407
2012-12-31	0.309
2013-12-31	0.257
2014-12-31	0.3884
2015-12-31	0.4511
2016-12-31	0.0106