Year	Percent
1979	15.78
1980	15.36
1981	8.41
1982	8.45
1983	2.32
1984	2.15
1985	1.58
1986	1.98
1987	1.07
1988	0.68
1989	0.62
1990	0.73
1991	16.33
1992	14
1993	9.85
1994	9.11
1995	14.03
1996	12.52
1997	17.07
1998	15.01
1999	13.66
2000	15.79
2001	15.52
2002	16.4
2003	15.32
2004	12.95
2005	12.06
2006	0.3243
2007	0.245
2008	0.5328
2009	0.3586
2010	0.6392
2011	0.6698
2013	3.4211
2014	2.0106
2015	6.1085