| Value | Category |
|---|---|
| 1 | have yob, mob - no imputation |
| 2 | yob, mod, yod, age at death - impute mob |
| 3 | yob, yod, aod - impute mob |
| 4 | yob,yod - impute mob |
| 5 | yob, aod - impute mob |
| 6 | mod,yod,aod - impute mob, yob |
| 7 | yod, aod - impute mob, yob |
| 8 | no information - impute mob, yob |
| 9 | none of the above |