| 时间 | 值 | 世界排名 |
|---|---|---|
| 2015 | 13.8 | 9 |
| 2014 | 12.7 | 7 |
| 2013 | 12.9 | 9 |
| 2012 | 12.6 | 10 |
| 2011 | 10.2 | 15 |
| 2010 | 11.3 | 16 |
| 2009 | 11.3 | 18 |
| 2008 | 8.4 | 18 |
| 2007 | 9.9 | 17 |
| 2006 | 7.9 | 20 |
| 2005 | 8.2 | 17 |
| 2004 | 9.3 | 12 |
| 2003 | 9.4 | 11 |
| 2002 | 10.2 | 7 |
| 2001 | 9.7 | 6 |
| 2000 | 9.1 | 4 |
| 1999 | 10.4 | 4 |
| 1998 | 9.6 | 5 |
| 1997 | 10.3 | 4 |
| 1996 | 10.7 | 4 |
| 1995 | 8.4 | 4 |
| 1994 | 9.8 | 3 |
| 1993 | 6.5 | 12 |
| 1992 | 6 | 12 |
| 1991 | 5.8 | 14 |
| 1990 | 3.8 | 32 |
| 1989 | 3.6 | 39 |
| 1988 | 2.6 | 64 |
| 1987 | 2.8 | 61 |
| 1986 | 5.5 | 20 |