| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [num] [noun] period | 132 |
|
| 2 | [prep] a [num] year period | 110 |
|
| 3 | [prep] a [num] year period | 110 |
|
| 4 | over [art] [num] year period | 94 |
|
| 5 | over [art] [num] year period | 94 |
|
| 6 | over a [num] year [noun sg] | 76 |
|
| 7 | over a [num] year [noun] | 76 |
|
| 8 | over a [adj] year period | 71 |
|
| 9 | over a [num] year period | 71 |
|
| 10 | over a [num] year period | 71 |
|
| 11 | over a [num] year period | 71 |
|
