| Value | Category | Cases | |
|---|---|---|---|
| 1 | a. One month | 3452 |
95.1%
|
| 2 | b. 3 months | 6 |
0.2%
|
| 3 | c. 6 months | 3 |
0.1%
|
| 4 | d. 12 months | 162 |
4.5%
|
| 5 | e. Others | 5 |
0.1%
|
| Sysmiss | 878 |