| Year | Answer | % Correct |
|---|---|---|
| 1976 | BT45 | 100%
|
| 1977 | BT45/BT45B | 100%
|
| 1978 | BT45C/BT46/BT46B/BT46C | 100%
|
| 1979 | BT46/BT48/BT49 | 100%
|
| 1982 | BT49C/BT49D/BT50 | 100%
|
| 1966 | BT19/BT20/BT22 | 94%
|
| 1967 | BT19/BT20/BT24 | 94%
|
| 1962 | BT3 | 94%
|
| 1972 | BT33/BT34/BT37 | 94%
|
| 1973 | BT37/BT42 | 94%
|
| 1963 | BT3/BT7 | 94%
|
| 1974 | BT42/BT44 | 94%
|
| 1983 | BT52/BT52B | 94%
|
| 1984 | BT53 | 94%
|
| 1985 | BT54 | 94%
|
| 1986 | BT54/BT55 | 94%
|
| 1987 | BT56 | 94%
|
| 1989 | BT58 | 94%
|
| 1990 | BT58/BT59 | 94%
|
| 1968 | BT24/BT26 | 89%
|
| 1970 | BT33 | 89%
|
| 1971 | BT33/BT34 | 89%
|
| 1980 | BT49 | 89%
|
| 1964 | BT7/BT11 | 89%
|
| 1965 | BT7/BT11 | 89%
|
| 1975 | BT44B | 72%
|
| 1981 | BT49C | 61%
|
| 1992 | BT60B | 50%
|
| 1969 | BT26A | 44%
|
| 1991 | BT59Y/BT60Y | 28%
|