| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.199 | 34 |
| 2015 | 8.244 | 24 |
| 2014 | 9.8 | 18 |
| 2013 | 11.722 | 13 |
| 2012 | 10.216 | 21 |
| 2011 | 8.838 | 23 |
| 2010 | 7.211 | 42 |
| 2009 | 7.814 | 48 |
| 2008 | 7.547 | 55 |
| 2007 | 6.993 | 53 |
| 2006 | 5.985 | 61 |
| 2005 | 5.534 | 60 |
| 2004 | 5.802 | 56 |
| 2003 | 7.11 | 50 |
| 2002 | 7.908 | 49 |
| 2001 | 9.153 | 45 |
| 2000 | 8.687 | 57 |
| 1999 | 9.438 | 54 |
| 1998 | 9.302 | 61 |
| 1997 | 8.114 | 74 |
| 1996 | 7.284 | 82 |
| 1995 | 6.043 | 94 |
| 1994 | 6.403 | 84 |
| 1993 | 8.178 | 62 |
| 1992 | 10.466 | 50 |
| 1991 | 12.05 | 44 |
| 1990 | 12.04 | 41 |
| 1989 | 12 | 40 |
| 1988 | 12 | 33 |
| 1987 | 12 | 30 |
| 1986 | 12 | 28 |