| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.166 | 23 |
| 2015 | 8.337 | 23 |
| 2014 | 8.753 | 22 |
| 2013 | 6.264 | 47 |
| 2012 | 5.947 | 49 |
| 2011 | 6.931 | 43 |
| 2010 | 7.017 | 45 |
| 2009 | 9.278 | 26 |
| 2008 | 8.493 | 42 |
| 2007 | 7.976 | 43 |
| 2006 | 11.411 | 10 |
| 2005 | 8.079 | 38 |
| 2004 | 6.443 | 49 |
| 2003 | 10.59 | 25 |
| 2002 | 15.503 | 17 |
| 2001 | 15.482 | 16 |
| 2000 | 12.503 | 28 |
| 1999 | 25.738 | 11 |
| 1998 | 39.067 | 5 |
| 1997 | 20.014 | 20 |
| 1996 | 17.256 | 32 |
| 1995 | 16.718 | 33 |
| 1994 | 12.533 | 37 |
| 1993 | 14.548 | 36 |
| 1992 | 19.603 | 25 |
| 1991 | 23.317 | 23 |
| 1990 | 17.531 | 29 |
| 1989 | 18.628 | 21 |
| 1988 | 17.718 | 15 |
| 1987 | 16.784 | 14 |
| 1986 | 15.39 | 22 |