| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.3 | 15 |
| 2015 | 4.41 | 17 |
| 2014 | 4.51 | 19 |
| 2013 | 4.61 | 19 |
| 2012 | 4.68 | 17 |
| 2011 | 4.73 | 18 |
| 2010 | 4.77 | 19 |
| 2009 | 4.8 | 19 |
| 2008 | 4.8 | 21 |
| 2007 | 4.73 | 18 |
| 2006 | 4.63 | 23 |
| 2005 | 4.47 | 26 |
| 2004 | 4.31 | 32 |
| 2003 | 4.17 | 33 |
| 2002 | 4.06 | 37 |
| 2001 | 4.04 | 37 |
| 2000 | 4.04 | 36 |
| 1999 | 4.01 | 36 |
| 1998 | 3.95 | 38 |
| 1997 | 3.85 | 47 |
| 1996 | 3.71 | 53 |
| 1995 | 3.58 | 54 |
| 1994 | 6.16 | 8 |
| 1993 | 6.09 | 10 |
| 1992 | 6.05 | 10 |
| 1991 | 6.02 | 13 |
| 1990 | 5.91 | 17 |
| 1989 | 5.82 | 19 |
| 1988 | 6.05 | 17 |
| 1987 | 6.71 | 13 |
| 1986 | 7.72 | 7 |