| 年度 | 数值 | 单位 | 发布日期 |
|---|
| 1998/1999 | 1 | 吨/公顷 | 2026-9 |
| 1997/1998 | 1 | 吨/公顷 | 2026-9 |
| 1996/1997 | 1 | 吨/公顷 | 2026-9 |
| 1995/1996 | 1 | 吨/公顷 | 2026-9 |
| 1994/1995 | 1 | 吨/公顷 | 2026-9 |
| 1993/1994 | 0.8 | 吨/公顷 | 2026-9 |
| 1992/1993 | 0.8 | 吨/公顷 | 2026-9 |
| 1991/1992 | 0.75 | 吨/公顷 | 2026-9 |
| 1990/1991 | 0.8 | 吨/公顷 | 2026-9 |
| 1989/1990 | 0.727 | 吨/公顷 | 2026-9 |
| 1988/1989 | 2.5 | 吨/公顷 | 2026-9 |
| 1987/1988 | 2 | 吨/公顷 | 2026-9 |
| 1986/1987 | 2 | 吨/公顷 | 2026-9 |
| 1985/1986 | 0.889 | 吨/公顷 | 2026-9 |
| 1984/1985 | 1.5 | 吨/公顷 | 2026-9 |
| 1983/1984 | 1.188 | 吨/公顷 | 2026-9 |
| 1982/1983 | 1.333 | 吨/公顷 | 2026-9 |
| 1981/1982 | 1.438 | 吨/公顷 | 2026-9 |
| 1980/1981 | 1.381 | 吨/公顷 | 2026-9 |
| 1979/1980 | 3 | 吨/公顷 | 2026-9 |
| 1978/1979 | 2.046 | 吨/公顷 | 2026-9 |
| 1977/1978 | 1.75 | 吨/公顷 | 2026-9 |
| 1976/1977 | 1.623 | 吨/公顷 | 2026-9 |
| 1975/1976 | 2.4 | 吨/公顷 | 2026-9 |
| 1974/1975 | 2 | 吨/公顷 | 2026-9 |