| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.58 | 7 |
| 2015 | 4.31 | 13 |
| 2014 | 4.32 | 12 |
| 2013 | 4.3 | 11 |
| 2012 | 4.76 | 6 |
| 2011 | 5.53 | 5 |
| 2010 | 5.9 | 5 |
| 2009 | 6.58 | 5 |
| 2008 | 6.18 | 5 |
| 2007 | 6.03 | 5 |
| 2006 | 4.66 | 7 |
| 2005 | 4.8 | 8 |
| 2004 | 5.14 | 9 |
| 2003 | 6 | 9 |
| 2002 | 5.45 | 9 |
| 2001 | 5.89 | 8 |
| 2000 | 6.26 | 8 |
| 1999 | 6.28 | 8 |
| 1998 | 6.27 | 8 |
| 1997 | 6.13 | 9 |
| 1996 | 6.03 | 10 |
| 1995 | 4.45 | 17 |
| 1994 | 6.54 | 11 |
| 1993 | 6.98 | 11 |
| 1992 | 6.92 | 14 |
| 1991 | 9.97 | 7 |
| 1990 | 7.75 | 9 |
| 1989 | 9.07 | 6 |
| 1988 | 9.36 | 6 |
| 1987 | 9.58 | 7 |
| 1986 | 9.77 | 5 |