Table:
text: Boet van Dulmen
Motorcycle Grand Prix results
Motorcycle Grand Prix results
Year_ Class_ Team Points Rank_ Wins
1975 350cc Yamaha 3 36th 0
1976 250cc Yamaha 4 26th 0
1976 350cc Yamaha 6 24th 0
1976 500cc Suzuki 9 25th 0
1977 500cc Suzuki 3 27th 0
1978 500cc Suzuki 15 13th 0
1979 500cc Suzuki 50 6th 1
1980 500cc Yamaha 10 14th 0
1981 500cc Yamaha 64 6th 0
1982 500cc Yamaha 23 12th 0
1983 500cc Suzuki 17 11th 0
1984 500cc Suzuki 25 8th 0
1985 500cc Honda 18 10th 0
1986 500cc Honda 8 12th 0

Question: What is the average year with points less than 9 with a rank of 24 for Boet van Dulmen?