| 年度 | 数值 | 单位 | 发布日期 |
|---|
| 1990/1991 | 7 | 千公顷 | 2026-9 |
| 1989/1990 | 5 | 千公顷 | 2026-9 |
| 1988/1989 | 4 | 千公顷 | 2026-9 |
| 1987/1988 | 5 | 千公顷 | 2026-9 |
| 1986/1987 | 3 | 千公顷 | 2026-9 |
| 1985/1986 | 2 | 千公顷 | 2026-9 |
| 1984/1985 | 5 | 千公顷 | 2026-9 |
| 1983/1984 | 4 | 千公顷 | 2026-9 |
| 1982/1983 | 5 | 千公顷 | 2026-9 |
| 1981/1982 | 1 | 千公顷 | 2026-9 |
| 1980/1981 | 2 | 千公顷 | 2026-9 |
| 1979/1980 | 2 | 千公顷 | 2026-9 |
| 1978/1979 | 2 | 千公顷 | 2026-9 |
| 1977/1978 | 1 | 千公顷 | 2026-9 |
| 1976/1977 | 0 | 千公顷 | 2026-9 |
| 1975/1976 | 1 | 千公顷 | 2026-9 |
| 1974/1975 | 1 | 千公顷 | 2026-9 |
| 1973/1974 | 1 | 千公顷 | 2026-9 |
| 1972/1973 | 1 | 千公顷 | 2026-9 |
| 1971/1972 | 1 | 千公顷 | 2026-9 |
| 1970/1971 | 1 | 千公顷 | 2026-9 |
| 1969/1970 | 1 | 千公顷 | 2026-9 |
| 1968/1969 | 1 | 千公顷 | 2026-9 |
| 1967/1968 | 1 | 千公顷 | 2026-9 |
| 1966/1967 | 1 | 千公顷 | 2026-9 |
| 1965/1966 | 0 | 千公顷 | 2026-9 |
| 1964/1965 | 0 | 千公顷 | 2026-9 |