| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2004 | 45.1 | 25 |
| 2003 | 36.1 | 26 |
| 2002 | 42.4 | 22 |
| 2001 | 77.5 | 16 |
| 2000 | 80.4 | 13 |
| 1999 | 57 | 15 |
| 1998 | 67.9 | 14 |
| 1997 | 46.8 | 26 |
| 1996 | 47.6 | 13 |
| 1995 | 46.6 | 11 |
| 1994 | 54.9 | 12 |
| 1993 | 50.2 | 10 |
| 1992 | 46.8 | 7 |
| 1991 | 22.4 | 18 |
| 1990 | 30.4 | 17 |
| 1989 | 34.8 | 14 |
| 1988 | 18.6 | 19 |
| 1987 | 10.5 | 23 |
| 1986 | 11.8 | 22 |