| Value | Category | Cases | |
|---|---|---|---|
| 1 | (a) one month only | 242 |
50.1%
|
| 2 | (b) two months | 19 |
3.9%
|
| 3 | (c) three months | 148 |
30.6%
|
| 96 | (96) Other specify | 74 |
15.3%
|
| Sysmiss | 17 |