| Year
Rangeland type | 1990 | 1998 | 2006 | |||
| Area | Area | Area | ||||
| (ha) | (%) | (ha) | (%) | (ha) | (%) | |
| Rich rangeland | 6094 | 38.5 | 8294 | 44.0 | 9762 | 42.2 |
| Poor rangeland | 9720 | 61.5 | 10545 | 56.0 | 13350 | 57.8 |
| Total | 15814 | 100 | 18839 | 100 | 23112 | 100 |