1927 - 1950
1950 - 1958
1958 - 1959
1959 - 1968
1968 - 1974
1972 - 1974
1974 - 1978
1978 - 1979
1979 - 1982
1982 - 2001
1991 - 1992
2006 - 2007
since 2001
