| Value | Category | Cases | |
|---|---|---|---|
| 1 | none | 1533 |
95.5%
|
| 2 | once | 59 |
3.7%
|
| 3 | twice | 5 |
0.3%
|
| 4 | three times | 2 |
0.1%
|
| 5 | four times or more | 6 |
0.4%
|
| 7 | 1 |
0.1%
|
|
| Sysmiss | 176 |