1991
- 2 teams
1990
- 10 teams
1989
- 13 teams
1988
- 14 teams
1987
- 15 teams
1986
- 16 teams
1985
- 17 teams
1984
- 16 teams
1983
- 15 teams
1982
- 14 teams
1981
- 14 teams
1980
- 15 teams
1979
- 14 teams
1978
- 16 teams
1977
- 18 teams
1976
- 19 teams
1975
- 22 teams
1974
- 18 teams
1973
- 18 teams
1972
- 17 teams
1971
- 17 teams
1970
- 16 teams
1969
- 9 teams
1968
- 10 teams
1967
- 11 teams
1966
- 10 teams
1965
- 8 teams
1964
- 10 teams
1963
- 11 teams
1962
- 10 teams
1961
- 10 teams
1960
- 9 teams
1959
- 7 teams
1958
- 6 teams
1957
- 5 teams
1956
- 4 teams
1955
- 3 teams
1954
- 5 teams
1953
- 5 teams
1952
- 4 teams
1951
- 4 teams
1950
- 4 teams
1949
- 3 teams
1948
- 3 teams
