Year	Percent
1978	5.98
1979	5.8
1980	4.81
1982	4.49
1983	5.26
1984	4.6
1985	7.43
1986	9.95
1987	7.86
1988	6.01
1989	4.29
1991	3.82
1992	6.62
1993	7
1994	7.27
1995	6.98
1996	8.65
1997	5.44
1998	8.25
1999	9.59
2001	7.73
2002	11.25
2003	10.19
2004	10.85
2006	8.88
2007	8.8
2008	9.16
2009	12.91
2010	9.86
2011	9.22
2012	8.87
2013	9.34
2014	8.79
2015	9.35
2016	9.13