| Covers listed |
|
| 1920: | September, October, November, December, |
| 1921: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1922: | January, February, March, April, May, June, July/August, Vol 5 # 1 - September, October, November, December, |
| 1923: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1924: | January, February, March, April, May, June, July, August, September, October, November, Vol 10 No 3 December, |
| 1925: | Vol 10 No 4 February, March, April, May, June, July, August, September, October, November, December, |
| 1926: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1927: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1928: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1929: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1930: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1931: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1932: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1933: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1934: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1935: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1936: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1937: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1938: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1939: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1940: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1941: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1942: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1943: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1944: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1945: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1946: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1947: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1948: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1949: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1950: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1951: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1952: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1953: | January, February, March, April, May, June, July, August, September, October, November, December, |
| 1954: | January, February, March, April, May, June, July, August, |
| 1955: | March, May, July, September, November, |
| 1956: | January, March, May, July, September, November, |
| 1957: | January, March, May, July, September, November, |
| 1958: | January, March, May, July, September, November, |
| 1959: | January, March, May, July, September, November, |
| 1960: | January, March, May, July, September, November, |
| 1961: | January, March, May, July, September, November, |
| 1962: | January, March, May, July, September, November, |
| 1963: | January, March, May, July, September, November, |
| 1964: | January, March, May, July, September, November, |
| 1965: | January, March, May, July, August, September, October, November, December, |
| 1966: | January, February, March, April, May, June, July, August, September, October, November, December, Annual, |
| 1967: | January, February, March, April, May, June, July, August, September, October, November, December, Annual, |
| 1968: | January, February, March, April, May, June, July, August, September, October, November, December, Annual, |
| 1969: | January, February, March, April, May, June, July, August, September, October, November, December, Annual, |
| 1970: | January, February, March, April, May, June, July, August, September, October, November, December, Annual, |
| 1971: | January, February, March, April, May, June, |
