| 时间 | 值 | 世界排名 |
|---|---|---|
| 2015 | 3.1 | 93 |
| 2014 | 3.5 | 87 |
| 2013 | 2.8 | 113 |
| 2012 | 3.6 | 98 |
| 2011 | 4.2 | 72 |
| 2010 | 5.6 | 54 |
| 2009 | 6.7 | 43 |
| 2008 | 7 | 22 |
| 2007 | 6 | 38 |
| 2006 | 9 | 17 |
| 2005 | 10 | 11 |
| 2004 | 10.3 | 7 |
| 2003 | 13.8 | 4 |
| 2002 | 6.8 | 20 |
| 2001 | 5.2 | 31 |
| 2000 | 7.4 | 8 |
| 1999 | 8.1 | 6 |
| 1998 | 6.8 | 7 |
| 1997 | 8.9 | 6 |
| 1996 | 10.6 | 5 |
| 1995 | 6.2 | 14 |
| 1994 | 9 | 6 |
| 1993 | 8.5 | 3 |
| 1992 | 7.8 | 7 |
| 1991 | 10.7 | 2 |
| 1990 | 11.9 | 2 |
| 1989 | 7.9 | 8 |
| 1988 | 5.1 | 16 |
| 1987 | 9.7 | 6 |
| 1986 | 9.8 | 5 |