Year	Percent
1978-12-31	9.2519
1979-12-31	13.6819
1980-12-31	16.6067
1981-12-31	13.9355
1982-12-31	12.2499
1983-12-31	10.1199
1984-12-31	9.962
1985-12-31	12.2268
1986-12-31	10.9318
1987-12-31	9.6955
1988-12-31	10.3508
1989-12-31	13.8927
1990-12-31	14.7658
1991-12-31	11.5132
1992-12-31	9.6183
1993-12-31	5.9337
1994-12-31	5.5031
1995-12-31	6.6823
1996-12-31	6.023
1997-12-31	6.8355
1998-12-31	7.3376
1999-12-31	5.4447
2000-12-31	6.1071
2001-12-31	4.972
2002-12-31	3.9915
2003-12-31	3.6654
2004-12-31	4.575
2005-12-31	4.6942
2006-12-31	4.7989
2007-12-31	5.9559
2008-12-31	5.5005
2009-12-31	1.1914
2010-12-31	0.6913
2011-12-31	0.889
2012-12-31	0.8369
2013-12-31	0.4929
2014-12-31	0.5393
2015-12-31	0.5529
2016-12-31	0.4902