| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [prep] the last 15 years | 23 |
|
| 2 | [noun sg] [prep] the [num ord] 15 years | 21 |
|
| 3 | [noun] over the [num ord] 15 years | 18 |
|
| 4 | [noun pl] [prep] the [num ord] 15 years | 12 |
|
| 5 | [noun] [prep] the next 15 years | 11 |
|
| 6 | [noun] for the [num ord] 15 years | 6 |
|
