| 时间 | 值 | 世界排名 |
|---|---|---|
| 2015 | 7.4 | 30 |
| 2014 | 6.7 | 25 |
| 2013 | 6.5 | 37 |
| 2012 | 7.3 | 27 |
| 2011 | 7.7 | 23 |
| 2010 | 9.1 | 22 |
| 2009 | 9.8 | 20 |
| 2008 | 6.1 | 29 |
| 2007 | 5.9 | 39 |
| 2006 | 5.1 | 44 |
| 2005 | 4.4 | 50 |
| 2004 | 5.1 | 41 |
| 2003 | 5.4 | 42 |
| 2002 | 5.8 | 32 |
| 2001 | 5.2 | 28 |
| 2000 | 5.1 | 27 |
| 1999 | 6.7 | 10 |
| 1998 | 6.4 | 13 |
| 1997 | 4.1 | 40 |
| 1996 | 5.1 | 23 |
| 1995 | 5 | 27 |
| 1994 | 5.4 | 25 |
| 1993 | 5.4 | 20 |
| 1992 | 5.1 | 21 |
| 1991 | 4.8 | 25 |
| 1990 | 4.4 | 25 |
| 1989 | 4.3 | 28 |
| 1988 | 3.6 | 38 |
| 1987 | 3.8 | 41 |
| 1986 | 3.7 | 42 |