| 时间 | 值 | 世界排名 |
|---|---|---|
| 2016 | 0.3 | 70 |
| 2015 | 0.3 | 140 |
| 2014 | 0.2 | 145 |
| 2013 | 0.2 | 157 |
| 2012 | 0.3 | 160 |
| 2011 | 0.2 | 159 |
| 2010 | 0.3 | 159 |
| 2009 | 0.3 | 160 |
| 2008 | 0.2 | 157 |
| 2007 | 2.1 | 127 |
| 2006 | 2.5 | 113 |
| 2005 | 3 | 83 |
| 2004 | 4.2 | 55 |
| 2003 | 6.5 | 25 |
| 2002 | 6.2 | 28 |
| 2001 | 4.8 | 37 |
| 2000 | 3.5 | 58 |
| 1999 | 4.6 | 43 |
| 1998 | 5.3 | 27 |
| 1997 | 5.2 | 23 |
| 1996 | 5.4 | 19 |
| 1995 | 5.2 | 21 |
| 1994 | 7.4 | 10 |
| 1993 | 6.2 | 13 |
| 1992 | 5.6 | 16 |
| 1991 | 6.5 | 12 |
| 1990 | 7.6 | 8 |
| 1989 | 9.5 | 4 |
| 1988 | 11.1 | 2 |
| 1987 | 14 | 2 |
| 1986 | 14.3 | 2 |