| 年度 | 数值 | 单位 | 发布日期 |
|---|
| 1990/1991 | 1 | 吨/公顷 | 2026-9 |
| 1989/1990 | 1 | 吨/公顷 | 2026-9 |
| 1988/1989 | 1 | 吨/公顷 | 2026-9 |
| 1987/1988 | 1 | 吨/公顷 | 2026-9 |
| 1986/1987 | 0.333 | 吨/公顷 | 2026-9 |
| 1985/1986 | 0.333 | 吨/公顷 | 2026-9 |
| 1984/1985 | 0.333 | 吨/公顷 | 2026-9 |
| 1983/1984 | 0.333 | 吨/公顷 | 2026-9 |
| 1982/1983 | 0.333 | 吨/公顷 | 2026-9 |
| 1981/1982 | 0.333 | 吨/公顷 | 2026-9 |
| 1980/1981 | 0.333 | 吨/公顷 | 2026-9 |
| 1979/1980 | 0.333 | 吨/公顷 | 2026-9 |
| 1978/1979 | 0.333 | 吨/公顷 | 2026-9 |
| 1977/1978 | 0.25 | 吨/公顷 | 2026-9 |
| 1976/1977 | 0.333 | 吨/公顷 | 2026-9 |
| 1975/1976 | 0.2 | 吨/公顷 | 2026-9 |
| 1974/1975 | 0.4 | 吨/公顷 | 2026-9 |
| 1973/1974 | 0.667 | 吨/公顷 | 2026-9 |
| 1972/1973 | 0.5 | 吨/公顷 | 2026-9 |
| 1971/1972 | 0.6 | 吨/公顷 | 2026-9 |
| 1970/1971 | 0.4 | 吨/公顷 | 2026-9 |
| 1969/1970 | 0.5 | 吨/公顷 | 2026-9 |