| 时间 | 值 | 世界排名 |
|---|---|---|
| 2015 | 2.6 | 103 |
| 2014 | 2.2 | 114 |
| 2013 | 2.7 | 115 |
| 2012 | 2.5 | 127 |
| 2011 | 3.3 | 103 |
| 2010 | 6.7 | 35 |
| 2009 | 7.4 | 37 |
| 2008 | 6 | 31 |
| 2007 | 7 | 27 |
| 2006 | 7.4 | 22 |
| 2005 | 7.3 | 19 |
| 2004 | 6.6 | 21 |
| 2003 | 8.6 | 13 |
| 2002 | 8.3 | 11 |
| 2001 | 7.5 | 9 |
| 2000 | 6.9 | 10 |
| 1999 | 8 | 7 |
| 1998 | 10.2 | 4 |
| 1997 | 10.5 | 3 |
| 1996 | 11.1 | 2 |
| 1995 | 10.7 | 2 |
| 1994 | 9.7 | 4 |
| 1993 | 9.6 | 2 |
| 1992 | 8.4 | 5 |
| 1991 | 4.8 | 26 |
| 1990 | 2.7 | 58 |
| 1989 | 2.2 | 70 |
| 1988 | 2 | 75 |
| 1987 | 2.6 | 68 |
| 1986 | 1.9 | 84 |