| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.51 | 34 |
| 2015 | 5.4 | 32 |
| 2014 | 5.36 | 32 |
| 2013 | 5.38 | 33 |
| 2012 | 5.45 | 33 |
| 2011 | 5.54 | 33 |
| 2010 | 5.66 | 36 |
| 2009 | 5.84 | 41 |
| 2008 | 6.05 | 53 |
| 2007 | 6.28 | 65 |
| 2006 | 6.48 | 67 |
| 2005 | 6.64 | 68 |
| 2004 | 6.77 | 71 |
| 2003 | 6.81 | 72 |
| 2002 | 6.78 | 72 |
| 2001 | 6.72 | 70 |
| 2000 | 6.68 | 70 |
| 1999 | 6.89 | 77 |
| 1998 | 7.1 | 81 |
| 1997 | 7.29 | 83 |
| 1996 | 7.41 | 87 |
| 1995 | 7.44 | 90 |
| 1994 | 7.52 | 91 |
| 1993 | 7.52 | 92 |
| 1992 | 7.46 | 93 |
| 1991 | 7.38 | 92 |
| 1990 | 7.33 | 90 |
| 1989 | 7.28 | 89 |
| 1988 | 7.3 | 91 |
| 1987 | 7.37 | 95 |
| 1986 | 7.47 | 99 |