| Number of people served | Number of utilities | Per cent of utilities (%) |
| less than 1000 | - | - |
| 1000 - 5000 | 3 | 12 |
| 5000 - 10,000 | 5 | 19 |
| 10,000 - 50,000 | 10 | 38 |
| 50,000 - 500,000 | 8 | 31 |
| more than 500,000 | - | - |