| 序号 | 时间 (年) |
数据 (千公顷) |
|---|---|---|
| 1 | 2020 | |
| 2 | 2011 | |
| 3 | 2009 | |
| 4 | 2008 | |
| 5 | 2007 | |
| 6 | 2006 | |
| 7 | 2005 | 0.18 |
| 8 | 2004 | 0.16 |
| 9 | 2003 | 0.31 |
| 10 | 2002 | 0.32 |
| 11 | 2001 | 0.36 |
| 12 | 2000 | 0.20 |
| 13 | 1999 | 0.41 |
| 14 | 1998 | 0.54 |
| 15 | 1997 | 0.79 |
| 16 | 1996 | 0.89 |
| 17 | 1995 | 1.31 |
| 18 | 1994 | 2.15 |
| 19 | 1993 | 5.20 |
| 20 | 1992 | 3.99 |
| 21 | 1991 | 4.57 |
| 22 | 1990 | 5.16 |
| 23 | 1989 | 5.14 |
| 24 | 1985 | 24.78 |
| 25 | 1980 | 11.51 |
| 26 | 1978 | 20.71 |
