| Study cluster | Number of mills | Average milling per year (t/year) | Average annual operations (months) | ||||
| Small | Medium | Large | Small | Medium | Large | ||
| Eastern | 15 | 564 | 4340 | 14,613 | 6 | 8 | 9 |
| Central | 16 | 1047 | 2667 | 10,167 | 8 | 7 | 9 |
| Western | 19 | 701 | 1923 | 7825 | 7 | 7 | 10 |
| Average | 17 | 738 | 2642 | 11,258 | 7 | 7 | 9 |