Year	Percent
1969	6
1970	6
1971	6
1972	6
1973	6
1974	6
1975	6
1976	6
1977	6
1978	6
1979	6
1980	6
1981	8
1982	13
1983	13
1984	13
1985	12
1986	12
1987	12
1988	12
1999	15