| Value | Category | Cases | |
|---|---|---|---|
| 1 | a. Once per month or more often | 2399 |
97.6%
|
| 2 | b. Once per every two months | 45 |
1.8%
|
| 3 | c. Once per every six months or year | 15 |
0.6%
|
| Sysmiss | 2047 |