| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a period of [noun sg] | 186 |
|
| 2 | over a period of time | 184 |
|
| 3 | over a period of time | 184 |
|
| 4 | over a period of [noun pl] | 110 |
|
| 5 | over a period of years | 62 |
|
| 6 | over a period of year | 62 |
|
| 7 | over a period of week | 19 |
|
| 8 | over a period of weeks | 19 |
|
| 9 | over a period of month | 17 |
|
| 10 | over a period of months | 17 |
|
