Year	Percent
1978-12-31	12.2253
1979-12-31	13.3694
1980-12-31	15.829
1981-12-31	13.8552
1982-12-31	12.2459
1983-12-31	10.3244
1984-12-31	10.2157
1985-12-31	11.9211
1986-12-31	10.7965
1987-12-31	9.7133
1988-12-31	10.4685
1989-12-31	13.8353
1990-12-31	14.6653
1991-12-31	11.2564
1992-12-31	9.5176
1993-12-31	5.8216
1994-12-31	5.7867
1995-12-31	6.8584
1996-12-31	6.0674
1997-12-31	6.9872
1998-12-31	7.2737
1999-12-31	5.53
2000-12-31	6.2312
2001-12-31	4.9439
2002-12-31	4.0988
2003-12-31	3.6936
2004-12-31	4.7068
2005-12-31	4.6941
2006-12-31	4.8669
2007-12-31	5.9906
2008-12-31	5.5762
2009-12-31	1.4077
2010-12-31	0.9526
2011-12-31	1.1692
2012-12-31	1.1036
2013-12-31	0.5906
2014-12-31	0.6485
2015-12-31	0.7385
2016-12-31	0.6935