Year	Percent
1978	5.78
1979	5.3
1980	5.01
1982	4.35
1983	5.4
1984	4.45
1985	7.11
1986	10.06
1987	7.76
1988	6.39
1989	4.23
1991	3.48
1992	5.45
1993	5.48
1994	5.61
1995	5.99
1996	6.83
1997	4.45
1998	5.7
1999	6.36
2001	5.06
2002	6.83
2003	5.83
2004	6.77
2006	6.37
2007	6.88
2008	6.42
2009	9.81
2010	7.58
2011	6.63
2012	6.36
2013	6.13
2014	6.23
2015	7.73
2016	6.23