| Covers listed | |
| 1967: | November, |
| 1968: | 11 October, 25 October, December, |
| 1969: | 14 March, |
| 1973: | November, |
| 1977: | December, |
| 1978: | February, |
| 1979: | May, |
| 1980: | February, |
| 1981: | January, September, |
| 1985: | April, June, |
| 1986: | June, |
| 1987: | March, 19 June, |
| 1988: | February, March, May, |
| 1989: | March, April, May, September, |
| 1998: | January, March, |
| 1999: | August, |
| 2000: | April, May, |
