| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] an [adj] per | 40 |
|
| 2 | [prep] an average [adj] | 33 |
|
| 3 | an average [adj] per | 21 |
|
| 4 | [prep] average [adj] per | 16 |
|
