| Value | Category |
|---|---|
| 1 | no intruption \ service continuously available |
| 2 | service disrupted once a month |
| 3 | service disrupted once a week |
| 4 | service disrupted more than once a week |
| 5 | service disrupted on daily basis |
| 6 | network not operating once a month |
| 7 | other |
| Sysmiss |