| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 8.689 | 14 |
| 2015 | 9.189 | 17 |
| 2014 | 8.373 | 25 |
| 2013 | 8.642 | 25 |
| 2012 | 11.572 | 11 |
| 2011 | 5.629 | 57 |
| 2010 | 4.557 | 67 |
| 2009 | 5.967 | 67 |
| 2008 | 5.302 | 78 |
| 2007 | 5.162 | 80 |
| 2006 | 5.139 | 66 |
| 2005 | 5.083 | 64 |
| 2004 | 2.433 | 115 |
| 2003 | 4.133 | 88 |
| 2002 | 5.487 | 69 |
| 2001 | 6.639 | 64 |
| 2000 | 8.101 | 66 |
| 1999 | 9.551 | 52 |
| 1998 | 18.401 | 23 |
| 1997 | 16.722 | 28 |
| 1996 | 17.591 | 30 |
| 1995 | 13.598 | 44 |
| 1990 | 13.667 | 34 |
| 1989 | 12 | 39 |
| 1988 | 10.333 | 39 |
| 1987 | 10.313 | 35 |
| 1986 | 11.25 | 32 |