| 年度 | 数值 | 单位 | 发布日期 |
|---|
| 1998/1999 | 6 | 千公顷 | 2026-9 |
| 1997/1998 | 5 | 千公顷 | 2026-9 |
| 1996/1997 | 4 | 千公顷 | 2026-9 |
| 1995/1996 | 4 | 千公顷 | 2026-9 |
| 1994/1995 | 3 | 千公顷 | 2026-9 |
| 1993/1994 | 5 | 千公顷 | 2026-9 |
| 1992/1993 | 5 | 千公顷 | 2026-9 |
| 1991/1992 | 7 | 千公顷 | 2026-9 |
| 1990/1991 | 5 | 千公顷 | 2026-9 |
| 1989/1990 | 13 | 千公顷 | 2026-9 |
| 1988/1989 | 14 | 千公顷 | 2026-9 |
| 1987/1988 | 13 | 千公顷 | 2026-9 |
| 1986/1987 | 12 | 千公顷 | 2026-9 |
| 1985/1986 | 13 | 千公顷 | 2026-9 |
| 1984/1985 | 12 | 千公顷 | 2026-9 |
| 1983/1984 | 13 | 千公顷 | 2026-9 |
| 1982/1983 | 14 | 千公顷 | 2026-9 |
| 1981/1982 | 15 | 千公顷 | 2026-9 |
| 1980/1981 | 15 | 千公顷 | 2026-9 |
| 1979/1980 | 15 | 千公顷 | 2026-9 |
| 1978/1979 | 46 | 千公顷 | 2026-9 |
| 1977/1978 | 50 | 千公顷 | 2026-9 |
| 1976/1977 | 58 | 千公顷 | 2026-9 |
| 1975/1976 | 43 | 千公顷 | 2026-9 |
| 1974/1975 | 87 | 千公顷 | 2026-9 |
| 1973/1974 | 15 | 千公顷 | 2026-9 |
| 1972/1973 | 73 | 千公顷 | 2026-9 |
| 1971/1972 | 82 | 千公顷 | 2026-9 |
| 1970/1971 | 78 | 千公顷 | 2026-9 |
| 1969/1970 | 64 | 千公顷 | 2026-9 |
| 1968/1969 | 61 | 千公顷 | 2026-9 |
| 1967/1968 | 60 | 千公顷 | 2026-9 |
| 1966/1967 | 61 | 千公顷 | 2026-9 |
| 1965/1966 | 63 | 千公顷 | 2026-9 |
| 1964/1965 | 67 | 千公顷 | 2026-9 |
| 1963/1964 | 68 | 千公顷 | 2026-9 |
| 1962/1963 | 68 | 千公顷 | 2026-9 |
| 1961/1962 | 79 | 千公顷 | 2026-9 |
| 1960/1961 | 78 | 千公顷 | 2026-9 |