| Value | Category | Cases | |
|---|---|---|---|
| 0 | very irregularly | 1362 |
16.5%
|
| 1 | less than 1 hour | 784 |
9.5%
|
| 2 | between 1 and 2 hours | 2184 |
26.5%
|
| 3 | between 2 and 4 hours | 2063 |
25%
|
| 4 | more than 4 hours | 1853 |
22.5%
|
| Sysmiss | 6830 |