| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [num] year ['s] duration | 60 |
|
| 2 | [prep] [num] year ['s] duration | 60 |
|
| 3 | of [num] year ['s] duration | 55 |
|
| 4 | of [num] year ['s] duration | 55 |
|
| 5 | [conj] [num] year ['s] duration | 13 |
|
| 6 | [coord] [num] year ['s] duration | 10 |
|
| 7 | or [num] year ['s] duration | 9 |
|
| 8 | or [num] year ['s] duration | 9 |
|
| 9 | [num] year ['s] duration [conj] | 5 |
|
