| 年度 | 数值 | 单位 | 发布日期 |
| 1998/1999 | 1 | 吨/公顷 | 2026-9 |
| 1997/1998 | 1.111 | 吨/公顷 | 2026-9 |
| 1996/1997 | 1.089 | 吨/公顷 | 2026-9 |
| 1995/1996 | 1.327 | 吨/公顷 | 2026-9 |
| 1994/1995 | 1.227 | 吨/公顷 | 2026-9 |
| 1993/1994 | 0.936 | 吨/公顷 | 2026-9 |
| 1992/1993 | 1.214 | 吨/公顷 | 2026-9 |
| 1991/1992 | 1.607 | 吨/公顷 | 2026-9 |
| 1990/1991 | 1.571 | 吨/公顷 | 2026-9 |
| 1989/1990 | 1.863 | 吨/公顷 | 2026-9 |
| 1988/1989 | 1.385 | 吨/公顷 | 2026-9 |
| 1987/1988 | 1.541 | 吨/公顷 | 2026-9 |
| 1986/1987 | 1.918 | 吨/公顷 | 2026-9 |
| 1985/1986 | 1.367 | 吨/公顷 | 2026-9 |
| 1984/1985 | 1.826 | 吨/公顷 | 2026-9 |
| 1983/1984 | 1.733 | 吨/公顷 | 2026-9 |
| 1982/1983 | 2.02 | 吨/公顷 | 2026-9 |
| 1981/1982 | 1.758 | 吨/公顷 | 2026-9 |
| 1980/1981 | 1.539 | 吨/公顷 | 2026-9 |
| 1979/1980 | 1.804 | 吨/公顷 | 2026-9 |
| 1978/1979 | 1.57 | 吨/公顷 | 2026-9 |
| 1977/1978 | 1.785 | 吨/公顷 | 2026-9 |
| 1976/1977 | 1.602 | 吨/公顷 | 2026-9 |
| 1975/1976 | 1.79 | 吨/公顷 | 2026-9 |
| 1974/1975 | 1.405 | 吨/公顷 | 2026-9 |
| 1973/1974 | 1.778 | 吨/公顷 | 2026-9 |
| 1972/1973 | 1.803 | 吨/公顷 | 2026-9 |