| Number (n) | Percentage (%) |
Less than 5 years | 21 | 24.7 |
5 - 9 years | 30 | 35.3 |
10 - 14 years | 18 | 21.2 |
15 - 19 years | 7 | 8.2 |
20 years and more | 9 | 10.6 |
Total | 85 | 100.0 |