May 1920 -Dec 1930
Feb 1931 -Oct 1938
Apr 1939 -Sep 1944
May 1945 -Apr 1948
Dec 1948 -Nov 1950
May 1951 -Dec 1952
May 1953 -Dec 1955
Mar 1956 -May 1957
Dec 1957 -May 1959
Dec 1959 -May 1961
Dec 1961 -May 1963
Jan 1964 -Feb 1965
May 1965 -Mar 1966