| Duration (Years) | Frequency | Percentage (%) |
| 1 - 10 | 23 | 19 |
| 11 - 20 | 27 | 22.3 |
| 21 - 30 | 27 | 22.3 |
| 31 - 40 | 23 | 19 |
| 41 - 50 | 10 | 8.3 |
| 51 above | 11 | 9.1 |
| Total | 121 | 100 |