November 1, 1968
September 1, 1967
May 1, 1961
January 1, 1960
April 1, 1955
January 1, 1950
May 1, 1945
August 1, 1943
April 1, 1942
February 1, 1941
February 1, 1932
December 1, 1930
December 19, 1920