• 1970 to 1971 1
• 1972 to 1973 0
• 1974 to 1975 0
• 1976 to 1977 0
• 1978 to 1979 0
• 1980 to 1981 0
• 1982 to 1983 0
• 1984 to 1985 0
• 1986 to 1987 0
• 1988 to 1988 1