| Value | Category | Cases | |
|---|---|---|---|
| 1 | Land frontier exhausted, fields are permanently cultivated | 43 |
39.1%
|
| 2 | Land frontier still open, but can be foreseen to close | 29 |
26.4%
|
| 3 | Land frontier open, no acute pressure on land | 38 |
34.5%
|
| -9 | 5 | ||
| -7 | 18 |