Year	Percent
1983	7.68
1984	6.37
1985	5.81
1986	4.48
1987	4.85
1988	4.43
1989	4.13
1990	4.12
1991	3.96
1992	2.61
1993	3.52
1994	3.04
1995	3.35
1996	1.84
1997	1.49
1998	1.38
1999	1.53
2000	1.29
2001	1.14
2002	1.33
2003	0.36
2004	0.77
2005	0.6
2006	0.42
2007	0.34
2008	0.5
2009	1.01
2010	0.74
2011	0.58
2012	0.66
2013	0.64
2014	0.55
2015	1.03
2016	1.09
2017	0.73