| Value | Category | Cases | |
|---|---|---|---|
| 1 | None | 4412 |
94.4%
|
| 2 | Once | 193 |
4.1%
|
| 3 | Twice | 33 |
0.7%
|
| 4 | Three times | 10 |
0.2%
|
| 5 | Four times or more | 25 |
0.5%
|
| Sysmiss | 1998 |