| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | an average of [n mass] [prep] | 42 |
|
| 2 | an average of [noun] per | 12 |
|
| 3 | an average of [noun] for | 11 |
|
| 4 | an average of [noun] of | 6 |
|
| 5 | an average of [noun] in | 5 |
|
