Year	Percent
1978-12-31	12.0576
1979-12-31	13.6902
1980-12-31	16.8694
1981-12-31	13.829
1982-12-31	12.3384
1983-12-31	10.1691
1984-12-31	9.9324
1985-12-31	12.4037
1986-12-31	10.9826
1987-12-31	9.6593
1988-12-31	10.0005
1989-12-31	13.7798
1990-12-31	14.7892
1991-12-31	11.7233
1992-12-31	9.6746
1993-12-31	5.9976
1994-12-31	5.2722
1995-12-31	6.5023
1996-12-31	5.9849
1997-12-31	6.6786
1998-12-31	7.3213
1999-12-31	5.3405
2000-12-31	5.9757
2001-12-31	5.003
2002-12-31	3.9309
2003-12-31	3.636
2004-12-31	4.451
2005-12-31	4.6711
2006-12-31	4.7343
2007-12-31	5.8017
2008-12-31	5.1604
2009-12-31	0.8127
2010-12-31	0.5629
2011-12-31	0.677
2012-12-31	0.6185
2013-12-31	0.4681
2014-12-31	0.4696
2015-12-31	0.4913
2016-12-31	0.417