Year	Percent
1978	6.4
1979	5.6
1980	6
1981	6.5
1982	7.9
1983	8.2
1984	7.6
1985	6
1986	4.7
1987	3
1988	3.3
1989	3.7
1990	2.8
1991	2.8
1992	3.5
1993	3.5
1994	5.6
1995	5.7
1996	5.2
1997	5.9