| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.19 | 50 |
| 2015 | 3.35 | 47 |
| 2014 | 3.51 | 44 |
| 2013 | 3.68 | 44 |
| 2012 | 3.84 | 36 |
| 2011 | 4 | 35 |
| 2010 | 4.1 | 33 |
| 2009 | 4.21 | 29 |
| 2008 | 4.35 | 30 |
| 2007 | 4.53 | 26 |
| 2006 | 4.73 | 20 |
| 2005 | 6.24 | 7 |
| 2004 | 6.59 | 5 |
| 2003 | 6.75 | 3 |
| 2002 | 6.84 | 3 |
| 2001 | 6.88 | 3 |
| 2000 | 6.96 | 2 |
| 1999 | 7.01 | 3 |
| 1998 | 6.77 | 4 |
| 1997 | 6.12 | 6 |
| 1996 | 5.23 | 9 |
| 1995 | 4.1 | 37 |
| 1994 | 3.19 | 68 |
| 1993 | 2.92 | 83 |
| 1992 | 3.49 | 71 |
| 1991 | 4.61 | 39 |
| 1990 | 5.95 | 16 |
| 1989 | 7.16 | 7 |
| 1988 | 8.03 | 4 |
| 1987 | 8.32 | 4 |
| 1986 | 8.12 | 4 |