| 年度 | 数值 | 单位 | 发布日期 |
|---|
| 1990/1991 | 2.33 | 吨/公顷 | 2026-9 |
| 1989/1990 | 2.537 | 吨/公顷 | 2026-9 |
| 1988/1989 | 2.212 | 吨/公顷 | 2026-9 |
| 1987/1988 | 2.25 | 吨/公顷 | 2026-9 |
| 1986/1987 | 2.452 | 吨/公顷 | 2026-9 |
| 1985/1986 | 1.723 | 吨/公顷 | 2026-9 |
| 1984/1985 | 1.759 | 吨/公顷 | 2026-9 |
| 1983/1984 | 1.819 | 吨/公顷 | 2026-9 |
| 1982/1983 | 1.784 | 吨/公顷 | 2026-9 |
| 1981/1982 | 2 | 吨/公顷 | 2026-9 |
| 1980/1981 | 1.781 | 吨/公顷 | 2026-9 |
| 1979/1980 | 1.618 | 吨/公顷 | 2026-9 |
| 1978/1979 | 1.826 | 吨/公顷 | 2026-9 |
| 1977/1978 | 1.645 | 吨/公顷 | 2026-9 |
| 1976/1977 | 2 | 吨/公顷 | 2026-9 |
| 1975/1976 | 1.84 | 吨/公顷 | 2026-9 |
| 1974/1975 | 1.941 | 吨/公顷 | 2026-9 |
| 1973/1974 | 1.857 | 吨/公顷 | 2026-9 |
| 1972/1973 | 2.111 | 吨/公顷 | 2026-9 |
| 1971/1972 | 2.111 | 吨/公顷 | 2026-9 |