| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over [art] [num] year period | 94 |
|
| 2 | over a [num] year period | 71 |
|
| 3 | over a [num] year period | 71 |
|
| 4 | over the [num] year period | 23 |
|
| 5 | over the [num] year period | 23 |
|
| 6 | over [art] five year period | 15 |
|
| 7 | over [art] three year period | 14 |
|
| 8 | over [art] two year period | 12 |
|
| 9 | over [art] 20 year period | 7 |
|
| 10 | over [art] ten year period | 7 |
|
