| Year | Date | Country | % Correct |
|---|---|---|---|
| 1961 | May 5 | United States | 98%
|
| 1961 | April 12 | Soviet Union | 97%
|
| 1982 | June 24 | France | 92%
|
| 1983 | November 28 | West Germany | 90%
|
| 1984 | October 5 | Canada | 88%
|
| 1984 | April 3 | India | 80%
|
| 1985 | November 26 | Mexico | 72%
|
| 1978 | June 27 | Poland | 71%
|
| 1985 | October 30 | Netherlands | 57%
|
| 1981 | May 14 | Romania | 55%
|
| 1979 | April 10 | Bulgaria | 53%
|
| 1980 | May 26 | Hungary | 53%
|
| 1978 | March 2 | Czechoslovakia | 50%
|
| 1978 | August 26 | East Germany | 47%
|
| 1980 | September 18 | Cuba | 32%
|
| 1980 | July 23 | Vietnam | 30%
|
| 1981 | March 22 | Mongolia | 25%
|
| 1985 | June 17 | Saudi Arabia | 20%
|
| 1988 | August 29 | Afghanistan | 16%
|
| 1987 | July 22 | Syria | 12%
|