| value | category | cases | |
|---|---|---|---|
| 1 | Month and year | 305 |
86.6%
|
| 5 | Year - m imp, a calc | 36 |
10.2%
|
| 7 | Month - date placed | 0 |
0%
|
| 8 | None - date placed | 11 |
3.1%
|
| 9 | From calendar | 0 |
0%
|
| Sysmiss | 1988 |