| Code figure | Meaning |
| 0 | Probability of event below lower limit |
| 1 | Probability of event above upper limit |
| 2 | Probability of event between lower and upper limits. The range includes the lower limit but not the upper limit. |
| 3 | Probability of event above lower limit |
| 4 | Probability of event below upper limit |
| 5-191 | Reserved |
| 192-254 | Reserved for local use |
| 255 | Missing |