| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] years ' duration | 71 |
|
| 2 | [num] years ' duration | 70 |
|
| 3 | four years ' duration | 27 |
|
| 4 | four years ' duration | 27 |
|
| 5 | three years ' duration | 25 |
|
| 6 | three years ' duration | 25 |
|
| 7 | two years ' duration | 7 |
|
| 8 | two years ' duration | 7 |
|
| 9 | years ' duration [conj] | 5 |
|
