| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2010 | 39.13 | 4 |
| 2009 | 32.41 | 12 |
| 2008 | 18.31 | 59 |
| 2007 | 38.72 | 24 |
| 2006 | 26.72 | 43 |
| 2005 | 7.87 | 131 |
| 2004 | 21.64 | 42 |
| 2003 | 20.07 | 44 |
| 2002 | 37.6 | 14 |
| 2001 | 13.72 | 84 |
| 2000 | 46.04 | 15 |
| 1999 | 78.36 | 5 |
| 1998 | 113.28 | 3 |
| 1997 | 65.76 | 8 |
| 1996 | 26.73 | 39 |
| 1995 | 16.4 | 73 |
| 1994 | 31.93 | 48 |
| 1993 | 64.59 | 15 |
| 1992 | 49.01 | 21 |
| 1991 | 15.73 | 71 |
| 1990 | 7.84 | 91 |