| Years in Service | Frequency | Percentage |
| Less than 5 years | 2 | 5% |
| 6 - 10 years | 3 | 8% |
| 11 - 15 years | 3 | 8% |
| 16 - 20 years | 13 | 35% |
| 21 - 25 years | 11 | 30% |
| 26 - 30 years | 5 | 14% |